Displaying publications 101 - 120 of 162 in total

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  1. Fulltext Characterisation of an antarctic yeast, glaciozyma antarctica pi12
    Teoh, Chul Peng, Koh, Soon Peng, Clemente Michael Wong Vui Ling
    Borneo International Journal of Biotechnology, 2020;1(1):89-102.
    MyJurnal
    Glaciozyma antarctica PI12 is a psychrophilic yeast isolated from Antarctica. It has an optimal growth in yeast peptone dextrose (YPD) and yeast mould (YM) broth media but not in potato dextrose (PD) broth medium. Early phase G. antarctica PI12 cells had elongated-shape and became oval-shaped as they aged. G. antarctica PI12 exhibited bipolar budding and formed a chain of cells during the lag and early exponential phases. The number of chains decreased as the yeast aged. It appeared mainly as a single cell at the stationary phase, and a small number of them still produced buds. Some cells at the stationary phase entered the quiescence state (G0) as a longterm survival strategy. The G. antarctica PI12 cell size decreased when they entered the stationary phase. G. antarctica PI12 was found to produce hydrolytic enzymes, chitinase, cellulase, mannanase, and xylanase. A higher glucose concentration of 2% in the PD agar medium inhibited the activities of chitinase but not the cellulase, mananase and xylanase.
    Matched MeSH terms: Saccharomyces cerevisiae
  2. Fulltext Antimicrobial properties of gynura procumbens (sambung nyawa) leaves in methanolic and acidic extracts
    Normah Haron, Hanapi Mat Jusoh
    International Journal of Allied Health Sciences, 2019;3(2):605-615.
    MyJurnal
    Gynura procumbens, commonly known as ‘sambung nyawa’ in Malaysia has been used
    traditionally as remedies for anti-inflammatory, anti-hyperlipidimic and anti-hyperglycemic. The
    purpose of the present study was to qualitatively evaluate the antimicrobial effects of Gynura procumbens extracts. effects of the sample were determined by disc diffusion method against two bacteria and two fungi namely E. coli, S. aureus, C. albicans and S. cerevisiae. The results showed that the acidic extract of G. procumbens has positive reactions towards E. coli, S. aureus and C. albicans with the presence of zone of inhibition at the concentration of 150 mg/mL. Following the positive reaction, the minimum inhibitory concentration (MIC) of the acidic extract was then evaluated by broth dilution method. The MIC of E. coli and S. aureus were determined at concentration 37.5 mg/mL and 75 mg/mL for C. albicans. It indicated that acidic extracts at lower concentration could inhibit the bacteria, but high concentration of extracts was required in the inhibition of the fungi. It can be concluded that, the present study proves that there is potential of antimicrobial effects in Gynura procumbens leaves extracts.
    Matched MeSH terms: Saccharomyces cerevisiae
  3. Fulltext Biofilm architecture of Candida rugosa and effect of amphotericin b, caspofungin, fluconazole and voriconazole on its structure
    Sri Raja Rajeswari Mahalingam, Priya Madhavan, Chong, Pei Pei
    Malaysian Journal of Medicine and Health Sciences, 2019;15(102):2-2.
    MyJurnal
    Introduction: One of the most common aetiology of opportunistic fungal infections in humans is Candida species. The virulence of Candida species is due to repertoire of factors, specifically, the ability to form biofilms. Medical devices such as intravenous catheters, prosthetic heart valves and surgical interventions provide pathogenic microorganisms with a surface to adhere to form biofilm. Fungi present as biofilms are often resistant to antifungal treatment because these biofilms offer a protective barrier that prohibits the drugs to get to the active site of the fungi. The objective of this study is to investigate the biofilm architecture of Candida rugosa (C.rugosa) at different developmental phases and to identify Sessile Minimum Inhibition Concentrations (SMICs) of amphotericin B, caspofungin, fluconazole, and voriconazole for the biofilm of C. rugosa. Methods: Confocal scanning laser microscopy (CSLM) and scanning electron microscopy (SEM) were used to visualize C. rugosa biofilms at different developmental phases. The antifungal susceptibility test was performed using serial doubling dilution. The growth kinetics of Candida biofilms was quantified using XTT reduction assay and crystal violet assay. Results: From the antifungal susceptibility test, the biofilms had SMIC of >16μg/mL for amphotericin B, 6µg/mL for caspofungin, >64μg/mL for fluconazole and >16μg/ mL for voriconazole. From the SEM micrographs, C. rugosa biofilm have a structure composed of an adherent yeast cells and blastopores with hyphal elements. There were significant alterations in the morphology after exposure to antifungal agents. The quantitative measurement of the matrix thickness of embedded yeast cells were obtained from CLSM micrographs. Conclusion: In conclusion, the ability of C. rugosa to form biofilms may attribute to one of the virulence factors that causes reduced susceptibility to antifungal agents.
    Matched MeSH terms: Saccharomyces cerevisiae
  4. Fulltext Disinfectant of pummelo (Citrus Grandis L. Osbeck) fruit juice using gaseous ozone
    Shah NNAK, Supian NAM, Hussein NA
    J Food Sci Technol, 2019 Jan;56(1):262-272.
    PMID: 30728568 DOI: 10.1007/s13197-018-3486-2
    This work studied the effectiveness of gaseous ozone disinfection on pummelo (Citrus Grandis L. Osbeck) fruit juice components. Unfiltered and filtered pummelo fruit juices were treated with gaseous ozone for up to 50 min with ozone concentration fixed at 600 mg/h. A microbiological and physicochemical properties analysis were conducted on the ozone-treated fruit juices samples. It was found that the survival rate of aerobic bacteria, yeast and mold in unfiltered pummelo fruit juice were higher compared to filtered juice, as the juice components acted as protective barriers to the microorganisms. The microorganisms' inactivation in pummelo fruit juices was also observed to have increased as the ozone treatment time increased. Significant effects on total colour difference, ascorbic acid content, and total phenolic content were also observed over increased ozone-treatment time. However, ozone was shown to be ineffective in activating PME activity in both types of juice. The experimental results of this study indicated that pummelo fruit juice components had significant effects on the effectiveness of gaseous ozone, however, the degree of the effects depends on the different fruit components (total soluble solids, total phenolic content). As a conclusion, filtered juice showed better quality characteristics in comparison to unfiltered juice post-ozone treatment.
    Matched MeSH terms: Saccharomyces cerevisiae
  5. Physical properties, storage stability, and consumer acceptability for sourdough bread produced using encapsulated kombucha sourdough starter culture
    Mohd Roby BH, Muhialdin BJ, Abadl MMT, Mat Nor NA, Marzlan AA, Lim SAH, et al.
    J Food Sci, 2020 Aug;85(8):2286-2295.
    PMID: 32691422 DOI: 10.1111/1750-3841.15302
    This study aimed to produce sourdough bread using an encapsulated kombucha sourdough starter culture without the addition of baker's yeast. The bioactive metabolites of kombucha sourdough starter and sourdough starter without kombucha were identified using 1 H-NMR analysis with multivariate analysis. The physical properties, including loaf volume, specific loaf volume, firmness, and water activity were determined following standard methods. The shelf life and consumer acceptability of the bread were also being evaluated. The principal component analyses showed the presence of 15 metabolites in kombucha sourdough starter. The major compounds that contributed to the differences from sourdough starter without kombucha were alpha-aminobutyric acid, alanine, acetic acid, riboflavin, pyridoxine, anserine, tryptophan, gluconic acid, and trehalose. The encapsulated kombucha sourdough starter increased the loaf volume (976.7 ± 25.2 mL) and specific loaf volume (4.38 ± 0.12 mL/g) compared to yeast bread. Thus, significant (P
    Matched MeSH terms: Saccharomyces cerevisiae
  6. Fulltext Application of supercritical carbon dioxide (SC-CO2 ) on the microbial and physicochemical quality of fresh chicken meat stored at chilling temperature
    Ismail Fitry Mohammad Rashedi, Safiullah Jauhar, Chong, ?Gun Hean, Nor Khaizura Mahmud @ Ab Rashid, Wan Zunairah Wan Ibadullah
    International Food Research Journal, 2020;27(1):103-110.
    MyJurnal
    Supercritical carbon dioxide (SC-CO2 ) is a non-thermal technique implemented by food, pharmaceutical, and similar industries with the aim of inhibiting the microorganisms and apply effective sterilisation. Presently, limited number of studies has reported the application of SC-CO2 on fresh chicken meat. The present work therefore aimed to reveal the microbial and physicochemical quality of the SC-CO2 -treated fresh chicken meat. The fresh chicken meat was subjected to the SC-CO2 at 14 MPa and 45°C for 40 min and was stored at 4°C for 0, 3, and 7 days. The obtained results indicated that the treatment with SC-CO2 significantly decreased the total plate count and, yeast and mould count from log10 5.90 to 2.00 CFU/g and from log10 5.02 to 2.00 CFU/g at day 7 of storage, respectively. The values of pH, cooking loss, and water holding capacity were not affected by the treatment. The results revealed that the SC-CO2 -treated samples displayed harder texture, higher lightness and yellowness, and lower redness. In addition, lipid peroxidation of SC-CO2 and control samples resulted in values of 1.9 and 0.5 MDA/mg of meat at day 7 of storage time and did not significantly change in the rest of the evaluation days. In summary, the application of SC-CO2 was capable of enhancing the microbial quality and certain physicochemical attributes. However, alteration of certain parameters of SC-CO2 might enhance the overall meat quality.
    Matched MeSH terms: Saccharomyces cerevisiae
  7. Fulltext Stable heterologous expression of biologically active terpenoids in green plant cells
    Ikram NK, Zhan X, Pan XW, King BC, Simonsen HT
    Front Plant Sci, 2015;6:129.
    PMID: 25852702 DOI: 10.3389/fpls.2015.00129
    Plants biosynthesize a great diversity of biologically active small molecules of interest for fragrances, flavors, and pharmaceuticals. Among specialized metabolites, terpenoids represent the greatest molecular diversity. Many terpenoids are very complex, and total chemical synthesis often requires many steps and difficult chemical reactions, resulting in a low final yield or incorrect stereochemistry. Several drug candidates with terpene skeletons are difficult to obtain by chemical synthesis due to their large number of chiral centers. Thus, biological production remains the preferred method for industrial production for many of these compounds. However, because these chemicals are often found in low abundance in the native plant, or are produced in plants which are difficult to cultivate, there is great interest in engineering increased production or expression of the biosynthetic pathways in heterologous hosts. Although there are many examples of successful engineering of microbes such as yeast or bacteria to produce these compounds, this often requires extensive changes to the host organism's metabolism. Optimization of plant gene expression, post-translational protein modifications, subcellular localization, and other factors often present challenges. To address the future demand for natural products used as drugs, new platforms are being established that are better suited for heterologous production of plant metabolites. Specifically, direct metabolic engineering of plants can provide effective heterologous expression for production of valuable plant-derived natural products. In this review, our primary focus is on small terpenoids and we discuss the benefits of plant expression platforms and provide several successful examples of stable production of small terpenoids in plants.
    Matched MeSH terms: Saccharomyces cerevisiae
  8. Fulltext AarF Domain Containing Kinase 3 (ADCK3) Mutant Cells Display Signs of Oxidative Stress, Defects in Mitochondrial Homeostasis and Lysosomal Accumulation
    Cullen JK, Abdul Murad N, Yeo A, McKenzie M, Ward M, Chong KL, et al.
    PLoS One, 2016;11(2):e0148213.
    PMID: 26866375 DOI: 10.1371/journal.pone.0148213
    Autosomal recessive ataxias are a clinically diverse group of syndromes that in some cases are caused by mutations in genes with roles in the DNA damage response, transcriptional regulation or mitochondrial function. One of these ataxias, known as Autosomal Recessive Cerebellar Ataxia Type-2 (ARCA-2, also known as SCAR9/COQ10D4; OMIM: #612016), arises due to mutations in the ADCK3 gene. The product of this gene (ADCK3) is an atypical kinase that is thought to play a regulatory role in coenzyme Q10 (CoQ10) biosynthesis. Although much work has been performed on the S. cerevisiae orthologue of ADCK3, the cellular and biochemical role of its mammalian counterpart, and why mutations in this gene lead to human disease is poorly understood. Here, we demonstrate that ADCK3 localises to mitochondrial cristae and is targeted to this organelle via the presence of an N-terminal localisation signal. Consistent with a role in CoQ10 biosynthesis, ADCK3 deficiency decreased cellular CoQ10 content. In addition, endogenous ADCK3 was found to associate in vitro with recombinant Coq3, Coq5, Coq7 and Coq9, components of the CoQ10 biosynthetic machinery. Furthermore, cell lines derived from ARCA-2 patients display signs of oxidative stress, defects in mitochondrial homeostasis and increases in lysosomal content. Together, these data shed light on the possible molecular role of ADCK3 and provide insight into the cellular pathways affected in ARCA-2 patients.
    Matched MeSH terms: Saccharomyces cerevisiae/metabolism; Saccharomyces cerevisiae Proteins/metabolism*
  9. Fulltext Dietary Prebiotics and Probiotics Influence the Growth Performance, Feed Utilisation, and Body Indices of Snakehead (Channa striata) Fingerlings
    Munir MB, Hashim R, Abdul Manaf MS, Nor SA
    Trop Life Sci Res, 2016 Aug;27(2):111-25.
    PMID: 27688855 MyJurnal DOI: 10.21315/tlsr2016.27.2.9
    This study used a two-phase feeding trial to determine the influence of selected dietary prebiotics and probiotics on growth performance, feed utilisation, and morphological changes in snakehead (Channa striata) fingerlings as well as the duration of these effects over a post-experimental period without supplementation. Triplicate groups of fish (22.46 ±0.17 g) were raised on six different treatment diets: three prebiotics (0.2% β-glucan, 1% galacto-oligosaccharides [GOS], 0.5% mannan-oligosaccharides [MOS]), two probiotics (1% live yeast [Saccharomyces cerevisiae] and 0.01% Lactobacillus acidophilus [LBA] powder) and a control (unsupplemented) diet; there were three replicates for each treatment. All diets contained 40% crude protein and 12% crude lipid. Fish were fed to satiation three times daily. No mortalities were recorded during Phase 1; however, 14% mortality was documented in the control and prebiotic-amended fish during Phase 2. At the end of Phase 1, growth performance and feed utilisation were significantly higher (p<0.05) in the LBA-treated fish, followed by live yeast treatment, compared with all other diets tested. The performance of fish on the three prebiotic diets were not significantly different from one another but was significantly higher than the control diet. During Phase 2 (the post-feeding phase), fish growth continued until the 6th week for the probiotic-based diets but levelled off after four weeks for the fish fed the prebiotic diets. The feed conversion ratio (FCR) was higher in all treatments during the post-feeding period. The hepatosomatic index (HSI) did not differ significantly among the tested diets. The visceral somatic index (VSI) and intraperitoneal fat (IPF) were highest in the LBA-based diet and the control diet, respectively. The body indices were significantly different (p<0.05) between Phases 1 and 2. This study demonstrates that probiotic-based diets have a more positive influence on the growth, feed utilisation, and survival of C. striata fingerlings compared with supplementation with prebiotics.
    Matched MeSH terms: Saccharomyces cerevisiae
  10. Fulltext Kinetic modelling of ethanol fermentation process using cassava (Manihot esculenta) starch as carbon source
    Low, C.Y., Hii, S.L., Leong, L.K., Yim, Y.Y., Tan, H.W.
    ASM Science Journal, 2012;6(1):61-66.
    MyJurnal
    Cassava starch was used as feedstock for production of bioethanol by Saccharomyces cerevisiae. The cassava starch was hydrolyzed using commercial α-amylase and glucoamylase enzymes followed by a batch ethanol fermentation process using saccharified starch slurry. By using 110 g/L of reducing sugar from saccharified starch slurry, the ethanol yield was promising with maximum ethanol concentration of 20.6 g/L recorded after 55 hours of cultivation process. Three different models - the Logistic model, Luedeking-Piret-like equation and Gompertz equation - were used to characterize and explain the cell growth, reducing sugar consumption and production formation, respectively. The kinetic parameters were estimated by fitting the experimental data to the proposed models using non-linear regression analysis. The correlation coefficient r2 values for the Logistic model, Luedeking-Piret-like equation and the Gompertz equation were 0.994, 0.996 and 0.990, respectively. The high correlation coefficient values indicate that the proposed models were able to describe the ethanol fermentation process.
    Matched MeSH terms: Saccharomyces cerevisiae
  11. Fulltext Cloning of gene encoding yeast alcohol dehydrogenase 1 (YADH 1) in Escherichia coli TOP10 for biocatalysis
    Mohd Rezuan M Aspar, Rashidah Abdul Rahim, Mohamad Hekarl Uzir
    Pertanika Journal of Science & Technology, 2011;19(2):423-430.
    MyJurnal
    Yeast producing alcohol dehydrogenase 1 (YADH 1) enzyme has been used as a biocatalyst for the synthesis of an optically active flavouring compound known as citronellol. However, the slow growth of yeast (Saccharomyces cerevisiae) has deterred the progress of biotransformation. The main purpose of this work is to clone the genes producing YADH1 enzyme from yeast into a faster growing bacteria, Escherichia coli. Initially, the sequence of the gene encoding this protein has been identified in the S. cerevisiae Genome Databases (SGD). The so-called Yadh1 gene sequence is located from coordinate 159548 to 160594 on chromosome XV of yeast. Based on this information, two primer sequences (Forward and Reverse) were constructed. Each of these primers will bind to either end of the Yadh1 gene. The Yadh1 gene was then amplified using Polymerase Chain Reaction (PCR) technique. The amplified Yadh 1 gene was successfully cloned into a cloning vector, TOPO TA plasmid. This plasmid also contains a gene which confers resistance to ampicillin. This recombinant
    plasmid was then inserted into Escherichia coli TOP 10 using heat shock protocol at 42oC. Finally, the cloned bacteria containing the recombinant TOPO TA plasmid harbouring Yadh1 gene was able to grow on Luria Bertani (LB) media supplied with antibiotic.
    Matched MeSH terms: Saccharomyces cerevisiae
  12. Cloning, Production and Characterization of a Glycoside Hydrolase Family 7 Enzyme from the Gut Microbiota of the Termite Coptotermes curvignathus
    Woon JS, King PJH, Mackeen MM, Mahadi NM, Wan Seman WMK, Broughton WJ, et al.
    Mol Biotechnol, 2017 Jul;59(7):271-283.
    PMID: 28573450 DOI: 10.1007/s12033-017-0015-x
    Coptotermes curvignathus is a termite that, owing to its ability to digest living trees, serves as a gold mine for robust industrial enzymes. This unique characteristic reflects the presence of very efficient hydrolytic enzyme systems including cellulases. Transcriptomic analyses of the gut of C. curvignathus revealed that carbohydrate-active enzymes (CAZy) were encoded by 3254 transcripts and that included 69 transcripts encoding glycoside hydrolase family 7 (GHF7) enzymes. Since GHF7 enzymes are useful to the biomass conversion industry, a gene encoding for a GHF7 enzyme (Gh1254) was synthesized, sub-cloned and expressed in the methylotrophic yeast Pichia pastoris. Expressed GH1254 had an apparent molecular mass of 42 kDa, but purification was hampered by its low expression levels in shaken flasks. To obtain more of the enzyme, GH1254 was produced in a bioreactor that resulted in a fourfold increase in crude enzyme levels. The purified enzyme was active towards soluble synthetic substrates such as 4-methylumbelliferyl-β-D-cellobioside, 4-nitrophenyl-β-D-cellobioside and 4-nitrophenyl-β-D-lactoside but was non-hydrolytic towards Avicel or carboxymethyl cellulose. GH1254 catalyzed optimally at 35 °C and maintained 70% of its activity at 25 °C. This enzyme is thus potentially useful in food industries employing low-temperature conditions.
    Matched MeSH terms: Saccharomyces cerevisiae
  13. Fulltext Fermented Brown Rice Flour as Functional Food Ingredient
    Ilowefah M, Chinma C, Bakar J, Ghazali HM, Muhammad K, Makeri M
    Foods, 2014 Feb 12;3(1):149-159.
    PMID: 28234309 DOI: 10.3390/foods3010149
    As fermentation could reduce the negative effects of bran on final cereal products, the utilization of whole-cereal flour is recommended, such as brown rice flour as a functional food ingredient. Therefore, this study aimed to investigate the effect of fermented brown rice flour on white rice flour, white rice batter and its steamed bread qualities. Brown rice batter was fermented using commercial baker's yeast (Eagle brand) according to the optimum conditions for moderate acidity (pH 5.5) to obtain fermented brown rice flour (FBRF). The FBRF was added to white rice flour at 0%, 10%, 20%, 30%, 40% and 50% levels to prepare steamed rice bread. Based on the sensory evaluation test, steamed rice bread containing 40% FBRF had the highest overall acceptability score. Thus, pasting properties of the composite rice flour, rheological properties of its batter, volume and texture properties of its steamed bread were determined. The results showed that peak viscosity of the rice flour containing 40% FBRF was significantly increased, whereas its breakdown, final viscosity and setback significantly decreased. Viscous, elastic and complex moduli of the batter having 40% FBRF were also significantly reduced. However, volume, specific volume, chewiness, resilience and cohesiveness of its steamed bread were significantly increased, while hardness and springiness significantly reduced in comparison to the control. These results established the effectiveness of yeast fermentation in reducing the detrimental effects of bran on the sensory properties of steamed white rice bread and encourage the usage of brown rice flour to enhance the quality of rice products.
    Matched MeSH terms: Saccharomyces cerevisiae
  14. Sequential saccharification and simultaneous fermentation (sssf) of sago hampas for the production of bioethanol
    Micky Vincent, Berry Rence Anak Senawi, Ennry Esut, Norizawati Muhammad Nor, Dayang Salwani Awang Adeni
    Sains Malaysiana, 2015;44:899-904.
    Bioethanol is a very environmentally friendly liquid biofuel that is not only renewable, but also sustainable. It is currently
    deemed as a highly suitable additive and substitute energy source to replace fossil based fuel. In this study, bioethanol
    was produced from sago hampas by using commercial amylase, cellulase and Saccharomyces cerevisiae via sequential
    saccharification and simultaneous fermentation (SSSF), a modified version of the simultaneous saccharification and
    fermentation (SSF) process. SSSF was performed on sago hampas at 2.5 and 5.0% (w/v) feedstock load for five days. The
    samples taken from the SSSF broths were analysed via high performance liquid chromatography (HPLC) for ethanol, glucose
    and acetic acid production. From the results obtained, SSSF with 5.0% sago hampas loading exhibited the highest ethanol
    production at 14.13 g/L (77.43% of theoretical ethanol yield), while SSSF using 2.5% sago hampas loading produced
    ethanol at 6.45 g/L (69.24% of theoretical ethanol yield). This study has shown that ethanol not only can be produced
    from sago hampas using different enzyme mixtures and S. cerevisiae via SSSF, but yields were also high, making this
    process highly promising for the production of cheap and sustainable ethanol as fuel.
    Matched MeSH terms: Saccharomyces cerevisiae
  15. Fulltext Cellobiohydrolase B of Aspergillus niger over-expressed in Pichia pastoris stimulates hydrolysis of oil palm empty fruit bunches
    Woon JS, Mackeen MM, Illias RM, Mahadi NM, Broughton WJ, Murad AMA, et al.
    PeerJ, 2017;5:e3909.
    PMID: 29038760 DOI: 10.7717/peerj.3909
    BACKGROUND: Aspergillus niger, along with many other lignocellulolytic fungi, has been widely used as a commercial workhorse for cellulase production. A fungal cellulase system generally includes three major classes of enzymes i.e., β-glucosidases, endoglucanases and cellobiohydrolases. Cellobiohydrolases (CBH) are vital to the degradation of crystalline cellulose present in lignocellulosic biomass. However, A. niger naturally secretes low levels of CBH. Hence, recombinant production of A. niger CBH is desirable to increase CBH production yield and also to allow biochemical characterisation of the recombinant CBH from A. niger.

    METHODS: In this study, the gene encoding a cellobiohydrolase B (cbhB) from A. niger ATCC 10574 was cloned and expressed in the methylotrophic yeast Pichia pastoris X-33. The recombinant CBHB was purified and characterised to study its biochemical and kinetic characteristics. To evaluate the potential of CBHB in assisting biomass conversion, CBHB was supplemented into a commercial cellulase preparation (Cellic(®) CTec2) and was used to hydrolyse oil palm empty fruit bunch (OPEFB), one of the most abundant lignocellulosic waste from the palm oil industry. To attain maximum saccharification, enzyme loadings were optimised by response surface methodology and the optimum point was validated experimentally. Hydrolysed OPEFB samples were analysed using attenuated total reflectance FTIR spectroscopy (ATR-FTIR) to screen for any compositional changes upon enzymatic treatment.

    RESULTS: Recombinant CBHB was over-expressed as a hyperglycosylated protein attached to N-glycans. CBHB was enzymatically active towards soluble substrates such as 4-methylumbelliferyl-β-D-cellobioside (MUC), p-nitrophenyl-cellobioside (pNPC) and p-nitrophenyl-cellobiotrioside (pNPG3) but was not active towards crystalline substrates like Avicel(®) and Sigmacell cellulose. Characterisation of purified CBHB using MUC as the model substrate revealed that optimum catalysis occurred at 50 °C and pH 4 but the enzyme was stable between pH 3 to 10 and 30 to 80 °C. Although CBHB on its own was unable to digest crystalline substrates, supplementation of CBHB (0.37%) with Cellic(®) CTec2 (30%) increased saccharification of OPEFB by 27%. Compositional analyses of the treated OPEFB samples revealed that CBHB supplementation reduced peak intensities of both crystalline cellulose Iα and Iβ in the treated OPEFB samples.

    DISCUSSION: Since CBHB alone was inactive against crystalline cellulose, these data suggested that it might work synergistically with other components of Cellic(®) CTec2. CBHB supplements were desirable as they further increased hydrolysis of OPEFB when the performance of Cellic(®) CTec2 was theoretically capped at an enzyme loading of 34% in this study. Hence, A. niger CBHB was identified as a potential supplementary enzyme for the enzymatic hydrolysis of OPEFB.

    Matched MeSH terms: Saccharomyces cerevisiae
  16. Social demographics determinants for resistome and microbiome variation of a multiethnic community in Southern Malaysia
    Dwiyanto J, Huët MAL, Hussain MH, Su TT, Tan JBL, Toh KY, et al.
    NPJ Biofilms Microbiomes, 2023 Aug 12;9(1):55.
    PMID: 37573460 DOI: 10.1038/s41522-023-00425-0
    The prevalence of antibiotic-resistant bacteria in Southeast Asia is a significant concern, yet there is limited research on the gut resistome and its correlation with lifestyle and environmental factors in the region. This study aimed to profile the gut resistome of 200 individuals in Malaysia using shotgun metagenomic sequencing and investigate its association with questionnaire data comprising demographic and lifestyle variables. A total of 1038 antibiotic resistance genes from 26 classes were detected with a mean carriage rate of 1.74 ± 1.18 gene copies per cell per person. Correlation analysis identified 14 environmental factors, including hygiene habits, health parameters, and intestinal colonization, that were significantly associated with the resistome (adjusted multivariate PERMANOVA, p 
    Matched MeSH terms: Saccharomyces cerevisiae
  17. Fungus isolated from dermatomycoses: a 9-month prospective study at Hospital Melaka
    Ng LC, Lee CS, Lim BB, Mohd Tap R, Tan XT, Tang MM
    Med J Malaysia, 2023 May;78(3):364-371.
    PMID: 37271847
    INTRODUCTION: Dermatomycoses are common superficial cutaneous fungal infections which affect the skin, nails and human hairs. It affects 20 to 25% of the world population. The causative fungus varies geographically across the globe. Study on dermatomycoses is crucial to identify the aetiological fungus involved locally. The study aimed to determine the causative fungus of superficial fungal infections of the skin, nail and hair in patients presented to Hospital Melaka.

    METHODS: This was a prospective study conducted from 15th January 2022 till 15th October 2022 at Dermatology Clinic, Hospital Melaka. Subjects with clinical dermatomycoses were included in this study. The samples were collected from skin, nails and hairs clinically affected by tinea corporis/cruris/pedis, onychomycosis and tinea capitis respectively. A potassium hydroxide (KOH) study was performed on the sample in which the fungal hyphae/yeast positive subjects were sent for fungal culture and fungal PCR test.

    RESULT: A total of 222 clinical samples from skin, nails and hairs with a clinical suspicion of dermatomycoses yielded fungal hyphae/yeast in KOH. Majority of the samples were collected from skin (138, 62.2%), followed by nails (65, 29.3%) and hairs (19, 8.6%). Male to female ratio was 1.18: 1. The age ranged from 2 to 87 with the median of 55.5-yearsold. Out of 222 samples, 150 (67.6%) were fungal culture positive. From fungal culture positive samples, 87 samples were from tinea corporis, 50 samples were from onychomycoses and 13 samples were from tinea capitis. Trichophyton rubrum (39, 44.8%) was the commonest dermatophyte isolated in tinea corporis/cruris/pedis. Nondermatophyte moulds (NDM, 35, 70%) were the main fungi isolated in onychomycosis. Microsporum canis (7/53.8%) was the principal causative fungus among patients with tinea capitis. Among 150 fungal culture positive samples, 76 were fungal PCR positive. Only 38 samples consistently isolated same fungal species in both fungal culture and PCR test.

    CONCLUSION: Majority of tinea corporis and tinea capitis fungal culture isolated dermatophytes, especially Trichophyton rubrum and Microsporum canis, respectively. Non-dermatophyte moulds were mainly isolated in onychomycosis.

    Matched MeSH terms: Saccharomyces cerevisiae
  18. Fulltext Key glycolytic branch influences mesocarp oil content in oil palm
    Ruzlan N, Low YSJ, Win W, Azizah Musa N, Ong AL, Chew FT, et al.
    Sci Rep, 2017 Aug 29;7(1):9626.
    PMID: 28852058 DOI: 10.1038/s41598-017-10195-3
    The fructose-1,6-bisphosphate aldolase catalyzed glycolysis branch that forms dihydroxyacetone phosphate and glyceraldehyde-3-phosphate was identified as a key driver of increased oil synthesis in oil palm and was validated in Saccharomyces cerevisiae. Reduction in triose phosphate isomerase (TPI) activity in a yeast knockdown mutant resulted in 19% increase in lipid content, while yeast strains overexpressing oil palm fructose-1,6-bisphosphate aldolase (EgFBA) and glycerol-3-phosphate dehydrogenase (EgG3PDH) showed increased lipid content by 16% and 21%, respectively. Genetic association analysis on oil palm SNPs of EgTPI SD_SNP_000035801 and EgGAPDH SD_SNP_000041011 showed that palms harboring homozygous GG in EgTPI and heterozygous AG in EgGAPDH exhibited higher mesocarp oil content based on dry weight. In addition, AG genotype of the SNP of EgG3PDH SD_SNP_000008411 was associated with higher mean mesocarp oil content, whereas GG genotype of the EgFBA SNP SD_SNP_000007765 was favourable. Additive effects were observed with a combination of favourable alleles in TPI and FBA in Nigerian x AVROS population (family F7) with highest allele frequency GG.GG being associated with a mean increase of 3.77% (p value = 2.3E-16) oil content over the Family 1. An analogous effect was observed in yeast, where overexpressed EgFBA in TPI - resulted in a 30% oil increment. These results provide insights into flux balances in glycolysis leading to higher yield in mesocarp oil-producing fruit.
    Matched MeSH terms: Saccharomyces cerevisiae/enzymology; Saccharomyces cerevisiae/genetics; Saccharomyces cerevisiae/metabolism
  19. Fulltext Preliminary screening of endophytic fungi from medicinal plants in malaysia for antimicrobial and antitumor activity
    Radu S, Kqueen CY
    Malays J Med Sci, 2002 Jul;9(2):23-33.
    PMID: 22844221 MyJurnal
    The screening of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria, yeast and fungi was carried out on isopropanol extracts prepared from 121 isolates of endophytic fungi isolated from medicinal plants in Malaysia. Sensitivity was found to vary among the microorganisms. Bacillus subtilis, Saccharomyces cerevisiae and Alternaria sp. were susceptible to extracts from three, two and two isolates of endophytic fungi, respectively. None were found effective against Salmonella typhimurium. Sixteen endophytic fungal isolates tested were also found to exhibit antitumor activity in the yeast cell-based assay.
    Matched MeSH terms: Saccharomyces cerevisiae
  20. Biphasic pretreatment excels over conventional sulfuric acid in pinewood biorefinery: An environmental analysis
    Khounani Z, Abdul Razak NN, Hosseinzadeh-Bandbafha H, Madadi M, Sun F, Mohammadi P, et al.
    Environ Res, 2024 May 01;248:118286.
    PMID: 38280524 DOI: 10.1016/j.envres.2024.118286
    This study assesses the environmental impact of pine chip-based biorefinery processes, focusing on bioethanol, xylonic acid, and lignin production. A cradle-to-gate Life Cycle Assessment (LCA) is employed, comparing a novel biphasic pretreatment method (p-toluenesulfonic acid (TsOH)/pentanol, Sc-1) with conventional sulfuric acid pretreatment (H2SO4, Sc-2). The analysis spans biomass handling, pretreatment, enzymatic hydrolysis, yeast fermentation, and distillation. Sc-1 yielded an environmental impact of 1.45E+01 kPt, predominantly affecting human health (96.55%), followed by ecosystems (3.07%) and resources (0.38%). Bioethanol, xylonic acid, and lignin contributed 32.61%, 29.28%, and 38.11% to the total environmental burdens, respectively. Sc-2 resulted in an environmental burden of 1.64E+01 kPt, with a primary impact on human health (96.56%) and smaller roles for ecosystems (3.07%) and resources (0.38%). Bioethanol, xylonic acid, and lignin contributed differently at 22.59%, 12.5%, and 64.91%, respectively. Electricity generation was predominant in both scenarios, accounting for 99.05% of the environmental impact, primarily driven by its extensive usage in biomass handling and pretreatment processes. Sc-1 demonstrated a 13.05% lower environmental impact than Sc-2 due to decreased electricity consumption and increased bioethanol and xylonic acid outputs. This study highlights the pivotal role of pretreatment methods in wood-based biorefineries and underscores the urgency of sustainable alternatives like TsOH/pentanol. Additionally, adopting greener electricity generation, advanced technologies, and process optimization are crucial for reducing the environmental footprint of waste-based biorefineries while preserving valuable bioproduct production.
    Matched MeSH terms: Saccharomyces cerevisiae
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