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Fulltext Effect on the physico-chemical properties of liberica green coffee beans under ambient storage

Ismail, I., Anuar, M.S., Shamsudin, R.

International Food Research Journal, 2013;20(1):255-264.
MyJurnal

Green coffee beans are stored for a certain period and under certain conditions until they are finally utilized. The storage period may depend on customer demand while the storage conditions depend on where the coffee beans are stored. Thus, this research emphasizes the physicochemical changes that occur in Liberica coffee beans during storage under the Malaysian
climate (average temperature and relative humidity of 29.33ºC and 71.75% respectively). The changes in the physico-chemical (coffee size, mass, densities, colour, proximate analysis, sucrose, chlorogenic acid content) and microbiological (yeast and mould count) properties were evaluated during eight months of storage. After the storage, the physical properties of the coffee changed as the coffee beans expanded in size, reduced in mass and density and became brighter in colour. Changes in the chemical properties were also detected where the moisture decreased and the ash content increased. In addition, the sucrose level was found to decrease with a corresponding increase in chlorogenic acid. During storage, the counts of yeast and mould were reduced. Model equations describing the changes in the properties were developed. The overall conclusion was that the coffee beans reduced in quality during storage.

Matched MeSH terms: Yeast, Dried
Fulltext Saprophytic yeasts: effective biocontrol agents against Aspergillus flavus

Afsah-Hejri, L.

International Food Research Journal, 2013;20(6):3403-3409.
MyJurnal

Aflatoxins are carcinogenic, mutagenic and teratogenic fungal toxins predominantly produced by Aspergillus flavus (A. flavus) and Aspergillus parasiticus (A. parasiticus). Members of the Aspergillus family are wound-invading pathogens that can infect pistachio trees and nuts. The pistachio nut is a favorite tree nut worldwide, and more than half of the world’s pistachio production is from Iran. Pistachio nuts can easily be infected with Aspergillus spp. due to early splitting or due to animal, insect or physical damage. Any established infection of Aspergillus under high relative humidity and temperature results in the production and rapid accumulation of aflatoxins in pistachio nuts. It is impractical to remove aflatoxins from pistachio nuts after they are produced. Some microorganisms (such as saprophytic yeasts) have been reported to have an antagonistic effect against Aspergillus spp. This study aimed to isolate saprophytic yeasts from pistachio fruits and leaves and investigate their biocontrol activities against a toxigenic strain of Aspergillus flavus (A. flavus). Saprophytic yeasts were identified based on their morphological properties and biochemical tests. In total, 24 yeast isolates were obtained from pistachio fruits and leaves, and their antagonistic effect on A. flavus (PTCC 5006) was investigated. Five saprophytic yeast isolates, displaying the highest biocontrol activities against A. flavus (PTCC 5006), were identified as Pseudozyma fusiformata, Cryptococcus albidus, Rhodotorula fragaria, Cryptococcus hungaricus and Rhodotorula hinula. The biocontrol activities of these yeast isolates were evaluated by their inhibitory effects on sporulation, colony expansion, biomass production and prevention of aflatoxin B1 (AFB1) production. Pseudozyma fusiformata was the most effective yeast isolate in terms of spore reduction (84.6%) and inhibition of AFB1 production (89.1%). Cryptococcus albidus produced the maximum reduction in fungal dry weight (77.9%). Based on these results, isolated saprophytic yeasts from pistachio fruits and leaves can be used as effective biocontrol agents against the growth of Aspergillus and aflatoxin production.

Matched MeSH terms: Yeast, Dried
Fulltext Effect of cornsilk (Maydis stigma) addition in yeast bread: investigation on nutritional compositions, textural properties and sensory acceptability

Ng, S.H., Wan Rosli, W.l.

International Food Research Journal, 2013;20(1):339-345.
MyJurnal

The proximate compositions, total dietary fibre (TDF) content, textural properties and sensory acceptability of yeast breads formulated with 0%, 2%, 4% and 6% of cornsilk powder (CSP) were studied. The protein, ash and TDF contents of yeast breads were increased in line with the CSP level added whereas moisture content was decreased. Yeast bread added with 6% CSP recorded the highest content of TDF (5.91%), protein (9.76%) and ash (1.03%) compared to other formulation of yeast breads containing lower percentage of CSP. Besides, texture profile analysis (TPA) reported that the firmness, gumminess and chewiness of yeast breads increased directly proportional to the level of CSP added mainly due to higher content of TDF and lower content of moisture. However, for the yeast bread added with 2%CSP, there were no significant differences compared with control yeast bread. Among all cornsilk-based yeast bread, formulation containing 2% CSP had the highest scores for all attributes including overall acceptance and there were no significant differences with control yeast bread. The present study indicated that the addition of 2% CSP could be an effective way to produce functional yeast bread without changing negatively its desirable textural and sensory acceptability.

Matched MeSH terms: Yeast, Dried
Fulltext Effect of postharvest storage of whole fruit on physico-chemical and microbial changes of fresh-cut cantaloupe (Cucumis melo L. reticulatus cv. Glamour)

Zainal Abidin, M., Shamsudin, R., Othman, Z., Abdul Rahman, R.

International Food Research Journal, 2013;20(2):953-960.
MyJurnal

Cantaloupes continue to ripen after harvesting which is caused by ethylene production due to climacteric behaviour during postharvest storage. In this study, the cantaloupe fruits harvested at commercial maturity were evaluated for quality attributes during three weeks of storage at 10°C and a relative humidity (RH) of 90±5%. In addition, fresh-cut samples were stored for a further 19 days at 2°C and 87% RH. The fresh-cut samples were prepared on a weekly basis by dipping into deionised water (control) at 2°C for 1 minute. The effect of postharvest storage of cantaloupe on the physico-chemical properties and microbial activity was observed prior to fresh-cut processing. It was found that firmness, luminosity (L*), and titratable acidity (TA) decreased, while total soluble solids (TSS), pH, TSS:TA ratio, microbial activity (total plate count (TPC) and yeast and mould (YM)) of the fresh-cut increased over the postharvest storage period of the fruit. Meanwhile, the orange colour and the intensity (hue angle, hab, and chromaticity) of the flesh did not differ significantly during storage. The cantaloupe stored for three weeks at a low temperature indicated a successful potential for fresh-cut processing due to good maintenance of the product quality.

Matched MeSH terms: Yeast, Dried
Fulltext A new source of Saccharomyces cerevisiae as a leavening agent in bread making

Noroul Asyikeen, Z., Ma’aruf, A.G., Sahilah, A.M., Mohd. Khan, A., Wan Aida, W.M.

International Food Research Journal, 2013;20(2):967-973.
MyJurnal

Megabiodiversity of Malaysian’s flora and fauna which include microorganism could be conserved and served as alternative source indigenous yeast, the leavening agent of commercial bread making. This study was conducted in attempt to exploit the potential of Saccharomyces cerevisiae strains isolated from 30 different local fruits and plant parts as a leavening agent in bread making. The enrichment was carried out by fermenting the plant samples in medium containing Grape Must at 25°C for 10 days following by isolation of tentative yeasts at 30°C for 3 to 5 days. 20 out of 30 samples tested showed the presence of yeasts was then selected for identification of S. cerevisiae strains through biochemical and physiological tests. Of the 20 yeast strains examined, 13 strains were identified as S. cerevisiae and potentially used as leavening agent in bread making where 5 strains namely SN3, SMK9, SDB10, SRB11 and SS12 showed better fermentative performance compared to commercial strains. Thus, indicated that the local fruits and plant parts could be the potential source of indigenous S. cerevisiae strains for leavening agent in bread making.

Matched MeSH terms: Yeast, Dried
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: Yeast, Dried
Fulltext Application of betel leaves (Piper betle L.) extract for preservation of homemade chili bo

Wendy Voon, W.Y, Ghali, N.A., Rukayadi, Y., Meor Hussin, A.S.

International Food Research Journal, 2014;21(6):2399-2403.
MyJurnal

This study is conducted to investigate the effect of different concentrations of betel leaves extract on color, pH and microbiological in homemade chili bo. The homemade chili bo with different concentrations (0 mg/ml, 0.75 mg/ml, 1.25 mg/ml and 1.75 mg/ml) of betel leaves extract were prepared for analysis. The results showed that the color of chili bo became darker as the concentration of betel leaves extract increased. The extract showed significant in the pH of chili bo after 7 days in which the highest concentration of extract showed the highest value of pH 4.31. The aerobic microbial count was decreased as the concentration of betel leaves extract increased in chili bo. After 7 days of storage, the highest concentration of betel leaves extract showed the highest percentage of reduction (6%), while the control sample showed 2.41% of aerobic reduction. The study also found that the extract contain lesser yeast and mold count (5.22 log CFU/ml) in homemade chili bo compared to the control sample (5.31 log CFU/ml) after 7 days. Betel leaves extract can be considered as natural food preservatives in chili bo to reduce the growth of spoilage microorganism and thus enhance the shelf life of chili bo.

Matched MeSH terms: Yeast, Dried
Fulltext In-vitro antidermatophytic activity of methanolic fractions from entada spiralis ridl. Stem bark and its bioautographic profile

Aiza Harun, Siti Zaiton Mat So’ad, Norazian Mohd Hassan, Neni Kartini Che Mohd Ramli

Pertanika Journal of Science & Technology, 2014;22(1):113-121.
MyJurnal

This study was performed to evaluate the antifungal activities of methanolic fractions from the stem bark of Entada spiralis Ridl. against human dermatophytes and yeast-like fungus in vitro. Three types of human dermatophyte, Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102 and Trichophyton tonsurans ATCC 28942, and one yeast-like fungus, Candida glabrata ATCC 66032, were tested against the methanolic fractions labelled FA1, FA4 and FA5. T. mentagrophytes, T. tonsuran and M. gypseum were susceptible to all tested fractions in a concentration-dependent manner whereas C. glabrata was resistant. Fraction FA1 at a concentration of 400 mg/mL was found to exhibit the highest antifungal activity with the inhibition zone diameter of 22 mm (T. mentagrophytes). This fraction showed a minimum inhibitory concentration MIC of 0.097 mg/mL while the MIC value for the fraction FA4 and fraction FA5 was 3.12 mg/ml and 1.56 mg/ml respectively. Agar overlay bioautography assay results showed that most of the bioactive compounds were found in the fraction FA1. Based on these findings, it can be concluded that the stem bark extracts of E. spiralis can be a future source of potent natural antimicrobial drugs for superficial skin diseases.

Matched MeSH terms: Yeast, Dried
Fulltext Phylogenetic and Transcripts Profiling of Glucose Sensing Related Genes in Candida glabrata

Ng TS, Mohd Desa MN, Sandai D, Chong PP, Than LT

Jundishapur J Microbiol, 2015 Nov;8(11):e25177.
PMID: 26855740 DOI: 10.5812/jjm.25177

BACKGROUND: The sensing mechanism of glucose in Saccharomyces cerevisiae is well studied. However, such information is scarcely found in other yeast species such as Candida glabrata.
OBJECTIVES: This study aimed to identify the glucose sensing pathway related genes of C. glabrata and to analyze the regulation pattern of these genes in response to different surrounding glucose concentrations through the quantitative real time polymerase chain reaction (qRT-PCR).
MATERIALS AND METHODS: Phylogenetic analysis was carried out on predicted amino acid sequences of C. glabrata and S. cerevisiae to compare their degree of similarity. In addition, the growth of C. glabrata in response to different amounts of glucose (0%, 0.01%, 0.1%, 1% and 2%) was evaluated via the spot dilution assay on prepared agar medium. Besides, the SNF3 and RGT2, which act as putative glucose sensors, and the RGT1 and MIG1, which act as putative transcriptional regulators and selected downstream hexose transporters (HXTs), were analysed through qRT-PCR analysis for the gene expression level under different glucose concentrations.
RESULTS: Comparative analysis of predicted amino acids in the phylogenetic tree showed high similarity between C. glabrata and S cerevisiae. Besides, C. glabrata demonstrated the capability to grow in glucose levels as low as 0.01% in the spot dilution assay. In qRT-PCR analysis, differential expressions were observed in selected genes when C. glabrata was subjected to different glucose concentrations.
CONCLUSIONS: The constructed phylogenetic tree suggests the close evolutionary relationship between C. glabrata and S. cerevisiae. The capability of C. glabrata to grow in extremely low glucose environments and the differential expression of selected glucose-sensing related genes suggested the possible role of these genes in modulating the growth of C. glabrata in response to different glucose concentrations. This study helps deepen our understanding of the glucose sensing mechanism in C. glabrata and serves to provide fundamental data that may assist in unveiling this mechanism as a potential drug target.

Matched MeSH terms: Yeast, Dried
Culture and molecular identification of fungal contaminants in edible bird nests

Chen JX, Wong SF, Lim PK, Mak JW

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2015;32(12):2138-47.
PMID: 26429550 DOI: 10.1080/19440049.2015.1101494

Widespread food poisoning due to microbial contamination has been a major concern for the food industry, consumers and governing authorities. This study is designed to determine the levels of fungal contamination in edible bird nests (EBNs) using culture and molecular techniques. Raw EBNs were collected from five house farms, and commercial EBNs were purchased from five Chinese traditional medicine shops (companies A-E) in Peninsular Malaysia. The fungal contents in the raw and commercial EBNs, and boiled and unboiled EBNs were determined. Culturable fungi were isolated and identified. In this study, the use of these methods revealed that all EBNs had fungal colony-forming units (CFUs) that exceeded the limit set by Standards and Industrial Research Institute of Malaysia (SIRIM) for yeast and moulds in EBNs. There was a significant difference (p < 0.05) in the number of types of fungi isolated from raw and commercial EBNs, but no significant difference in the reduction of the number of types of fungi after boiling the EBNs (p > 0.05). The types of fungi isolated from the unboiled raw EBNs were mainly soil, plant and environmental fungi, while the types of fungi isolated from the boiled raw EBNs, unboiled and boiled commercial EBNs were mainly environmental fungi. Aspergillus sp., Candida sp., Cladosporium sp., Neurospora sp. and Penicillum sp. were the most common fungi isolated from the unboiled and boiled raw and commercial EBNs. Some of these fungi are mycotoxin producers and cause opportunistic infections in humans. Further studies to determine the mycotoxin levels and methods to prevent or remove these contaminations from EBNs for safe consumption are necessary. The establishment and implementation of stringent regulations for the standards of EBNs should be regularly updated and monitored to improve the quality of the EBNs and consumer safety.

Matched MeSH terms: Yeast, Dried
Fulltext Numerical Analysis of Hydrodynamic Flow in Microfluidic Biochip for Single-Cell Trapping Application

Khalili AA, Ahmad MR

Int J Mol Sci, 2015;16(11):26770-85.
PMID: 26569218 DOI: 10.3390/ijms161125987

Single-cell analysis has become the interest of a wide range of biological and biomedical engineering research. It could provide precise information on individual cells, leading to important knowledge regarding human diseases. To perform single-cell analysis, it is crucial to isolate the individual cells before further manipulation is carried out. Recently, microfluidic biochips have been widely used for cell trapping and single cell analysis, such as mechanical and electrical detection. This work focuses on developing a finite element simulation model of single-cell trapping system for any types of cells or particles based on the hydrodynamic flow resistance (Rh) manipulations in the main channel and trap channel to achieve successful trapping. Analysis is carried out using finite element ABAQUS-FEA™ software. A guideline to design and optimize single-cell trapping model is proposed and the example of a thorough optimization analysis is carried out using a yeast cell model. The results show the finite element model is able to trap a single cell inside the fluidic environment. Fluid's velocity profile and streamline plots for successful and unsuccessful single yeast cell trapping are presented according to the hydrodynamic concept. The single-cell trapping model can be a significant important guideline in designing a new chip for biomedical applications.

Matched MeSH terms: Yeast, Dried
Fulltext Candida isolates from pregnant women and their antifungal susceptibility in a Malaysian tertiary-care hospital

Masri SN, Noor SM, Nor LA, Osman M, Rahman MM

Pak J Med Sci, 2015;31(3):658-61.
PMID: 26150863 DOI: 10.12669/pjms.313.7072

Pregnant women are susceptible to vaginal colonization and infection by yeast. The purpose of the study was to determine the prevalence of Candida spp in high vaginal swabs of pregnant women and their antifungal susceptibility.

Matched MeSH terms: Yeast, Dried
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: Yeast, Dried
Fulltext Effect of Vietnamese coriander (Persicaria odorata), turmeric (Curcuma longa) and asam gelugor (Garcinia atroviridis) leaf on the microbiological quality of gulai tempoyak paste

Abdul Aris, M. H., Lee, H. Y., Hussain, N., Ghazali, H., Nordin, W. N., Mahyudin, N. A.

International Food Research Journal, 2015;22(4):1657-1661.
MyJurnal

The objective of this study was to determine microbiological quality of gulai tempoyak paste (GTP) added with three different leaf; Vietnamese coriander, turmeric and asam gelugor. The GTP was cooked for 10 minutes with control temperature (60-70°C) and the leaf were added at 2, 5 and 8 minutes during the cooking time to give exposure times of 8, 5 and 2 minutes of the leaf to GTP. GTP without addition of leaf was treated as control and all the prepared GTPs were stored at 30°C for 2 days before analysed using total plate count (TPC) and yeast and mould count (YMC). The addition of asam gelugor leaf to GTP for 5 minutes of the cooking period significantly (p > 0.05) reduced TPC (log10 3.54 CFU/g) compared to Vietnamese coriander (log10 4.67 CFU/g) and turmeric leaf (log10 4.70 CFU/g). Asam gelugor leaf also showed a significant difference in TPC reduction (log10 4.44 CFU/g) when added to GTP for 8 minutes compared to Vietnamese coriander (log10 5.10 CFU/g), but was insignificant to turmeric leaf (log10 4.71 CFU/g). In conclusion, there are significant effects on microbiological quality of GTP when added with Vietnamese coriander, turmeric and asam gelugor leaf at different exposure time based on TPC and YMC.

Matched MeSH terms: Yeast, Dried
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: Yeast, Dried
Fulltext Antimicrobial activity and chemical composition of Pistacia chinensis Bunge leaves

Rashed, K., Said, A., Abdo, A., Selim, S.

International Food Research Journal, 2016;23(1):316-321.
MyJurnal

This work was carried out for determining antimicrobial activity of Pistacia chinensis leaves
methanol extract and identifying the chemical composition of the plant extract. Methanol extract
was tested for antimicrobial activity using disc-diffusion assay and the extract was fractionated
on silica gel column chromatography for the isolation of the bio-active constituents. The leaves
extract of P. chinensis showed a significant antimicrobial effect, it strongly inhibited the growth
of the test bacteria and yeast studied. Chromatograpic separation of the methanol extract of
P. chinensis leaves has led to the isolation and characterization of β-sitosterol, luepol, and
six flavonoids, quercetin, myricetin, quercetin 3-O-α-rhamnoside, quercetin 3-O-β-glucoside,
myricetin 3-O-α-rhamnoside and myricetin 3-O-β-glucuronide using various chromatographic
procedures and the interpretation of spectral data in comparison with already existing data
reported in the literature. The results presented here may suggest that the leaves extract of P.
chinensis possess antimicrobial properties, and therefore, can be used as natural preservative
ingredients in food and/or pharmaceuticals.

Matched MeSH terms: Yeast, Dried
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: Yeast, Dried
Screening and identification of host proteins interacting with Toxoplasma gondii SAG2 by yeast two-hybrid assay

Lai MY, Lau YL

Parasit Vectors, 2017 Oct 02;10(1):456.
PMID: 28969712 DOI: 10.1186/s13071-017-2387-y

BACKGROUND: The identification of receptors or binding partners of Toxoplasma gondii from humans is an essential activity. Many proteins involved in T. gondii invasion have been characterized, and their contribution for parasite entry has been proposed. However, their molecular interactions remain unclear.
RESULTS: Yeast two-hybrid (Y2H) experiment was used to identify the binding partners of surface antigens of T. gondii by using SAG2 as bait. Colony PCR was performed and positive clones were sent for sequencing to confirm their identity. The yeast plasmids for true positive clones were rescued by transformation into E. coli TOP 10F' cells. The interplay between bait and prey was confirmed by β-galactosidase assay and co-immunoprecipitation experiment. We detected 20 clones interacting with SAG2 based on a series of the selection procedures. Following the autoactivation and toxicity tests, SAG2 was proven to be a suitable candidate as a bait. Thirteen clones were further examined by small scale Y2H experiment. The results indicated that a strong interaction existed between Homo sapiens zinc finger protein and SAG2, which could activate the expressions of the reporter genes in diploid yeast. Co-immunoprecipitation experiment result indicated the binding between this prey and SAG2 protein was significant (Mann-Whitney U-test: Z = -1.964, P = 0.05).
CONCLUSIONS: Homo sapiens zinc finger protein was found to interact with SAG2. To improve the understanding of this prey protein's function, advanced investigations need to be carried out.

Matched MeSH terms: Yeast, Dried
Fulltext Research progress in Bioflocculants from bacteria

Abdullah, A.M., Hamidah, H., Alam, M.Z.

International Food Research Journal, 2017;24(101):0-0.
MyJurnal

Although one of the major users of flocculants are water and wastewater treatment industries, flocculants are also used in various food industries. The chemical flocculants are preferred widely in these industries due to low production cost and fast production ability. However, the negative effects of the chemical flocculants should not be neglected to gain the economic benefits only. Therefore, the researchers are working to discover efficient and economical flocculants from biological sources. Several attempts have been made and are still being made to extract or produce bioflocculants from natural sources such as plants, bacteria, fungi, yeast, algae, etc. The review revealed that significant amount of work have been done in the past, in search of bioflocculant. However, commercially viable bioflocculants are yet to be marketed widely. With the advent of new biotechnologies and advances in genetic engineering, the researchers are hopeful to discover or develop commercially viable, safe and environmentfriendly bioflocculants.

Matched MeSH terms: Yeast, Dried
Fulltext Optimum media compositions for bioprotein production by mixed culture of Phanerochaete Chrysosporium and Candida Utilis using palm kernel cake and seaweed as substrates

Ilias, N.N., Jamal, P., Sulaiman, S., Jaswir, I., Ansari, A.H., Azmi, A.S., et al.

International Food Research Journal, 2017;24(101):0-0.
MyJurnal

Bioprotein is one of the useful products obtained from biotechnology invention. It is a promising replacement for the commercial fish feed supplement. In this study, the enrichment of the bioprotein content after solid state fermentation using palm kernel cake and seaweed by the white rot fungus: Phanerochaete chrysoporium and yeast: Candida utilis was carried out. The growth media components were selected from 11 types of media using Plackett-Burman design (hereinafter PBD) and were optimized by one-factor-at-a-time (OFAT) method with bioprotein concentration (mg/g) as the response. From the screening result using PBD, three media components, namely K2HPO4, CuSO4.5H2O and MnSO4.H2O were selected for further optimization using OFAT method because of their positive contributions to the response. The final results showed that 5.0 g/L K2HPO4, 3.0 g/L CuSO4.5H2O and 0.1 g/L MnSO4.H2O were there to be the optimum media constituents with 9.0 g/L, MgSO4.7H2O, 0.1 g/L, CaCl2.H2O, 3.0 g/L FeSO4.7H2O and 3.0 g/L peptone as fixed compositions. At this optimum concentration, the protein increment of 11% was observed as compared to the results determined in the screening using PBD. The study revealed the benefits of using mixed cultures in improving the protein concentrations which can be used as nutritious fish feed.

Matched MeSH terms: Yeast, Dried

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