Displaying publications 1 - 20 of 62 in total

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  1. Wong CL, Yong CY, Muhamad A, Syahir A, Omar AR, Sieo CC, et al.
    Appl Microbiol Biotechnol, 2018 May;102(9):4131-4142.
    PMID: 29564523 DOI: 10.1007/s00253-018-8921-9
    Foot-and-mouth disease (FMD) is a major threat to the livestock industry worldwide. Despite constant surveillance and effective vaccination, the perpetual mutations of the foot-and-mouth disease virus (FMDV) pose a huge challenge to FMD diagnosis. The immunodominant region of the FMDV VP1 protein (residues 131-170) displayed on phage T7 has been used to detect anti-FMDV in bovine sera. In the present study, the functional epitope was further delineated using amino acid sequence alignment, homology modelling and phage display. Two highly conserved regions (VP1145-152 and VP1159-170) were identified among different FMDV serotypes. The coding regions of these two epitopes were fused separately to the T7 genome and displayed on the phage particles. Interestingly, chimeric phage displaying the VP1159-170 epitope demonstrated a higher antigenicity than that displaying the VP1131-170 epitope. By contrast, phage T7 displaying the VP1145-152 epitope did not react significantly with the anti-FMDV antibodies in vaccinated bovine sera. This study has successfully identified a smaller functional epitope, VP1159-170, located at the C-terminal end of the structural VP1 protein. The phage T7 displaying this shorter epitope is a promising diagnostic reagent to detect anti-FMDV antibodies in vaccinated animals.
  2. Ong SY, Zainab-L I, Pyary S, Sudesh K
    Appl Microbiol Biotechnol, 2018 Mar;102(5):2117-2127.
    PMID: 29404644 DOI: 10.1007/s00253-018-8788-9
    Polyhydroxyalkanoate (PHA) is a family of microbial polyesters that is completely biodegradable and possesses the mechanical and thermal properties of some commonly used petrochemical-based plastics. Therefore, PHA is attractive as a biodegradable thermoplastic. It has always been a challenge to commercialize PHA due to the high cost involved in the biosynthesis of PHA via bacterial fermentation and the subsequent purification of the synthesized PHA from bacterial cells. Innovative enterprise by researchers from various disciplines over several decades successfully reduced the cost of PHA production through the efficient use of cheap and renewable feedstock, precisely controlled fermentation process, and customized bacterial strains. Despite the fact that PHA yields have been improved tremendously, the recovery and purification processes of PHA from bacterial cells remain exhaustive and require large amounts of water and high energy input besides some chemicals. In addition, the residual cell biomass ends up as waste that needs to be treated. We have found that some animals can readily feed on the dried bacterial cells that contain PHA granules. The digestive system of the animals is able to assimilate the bacterial cells but not the PHA granules which are excreted in the form of fecal pellets, thus resulting in partial recovery and purification of PHA. In this mini-review, we will discuss this new concept of biological recovery, the selection of the animal model for biological recovery, and the properties and possible applications of the biologically recovered PHA.
  3. Chan ES, Lee PP, Ravindra P, Krishnaiah K, Voo WP
    Appl Microbiol Biotechnol, 2010 Mar;86(1):385-91.
    PMID: 20033402 DOI: 10.1007/s00253-009-2384-y
    The aim of this work was to develop a standard quantitative method to measure the acid tolerance of probiotic cells when exposed to a simulated gastric fluid. Three model strains of different cell concentrations were exposed to a standard simulated gastric fluid of fixed volume. The fluid pH ranged from pH 1.5 to 2.5. In general, the death kinetics followed an exponential trend. The overall death constant, k (d), for all strains was found to be in a power relationship with the pH value and the initial cell concentration, and it can be expressed as k(d)=k(AII) (pH(-9.0)N(0)(-0.19)) where k (AII) is defined as the acid intolerance indicator and N (0) is the initial cell concentration (CFU/ml). This equation was validated with the experimental data with an average R (2) of 0.98. The acid intolerance of cells can be quantitatively expressed by the k (AII) values, where higher value indicates higher intolerance. In conclusion, a standard quantitative method has been developed to measure the acid tolerance of probiotic cells. This could facilitate the selection of probiotic strains and processing technologies.
  4. Jiang L, Huang P, Ren B, Song Z, Zhu G, He W, et al.
    Appl Microbiol Biotechnol, 2021 Jun;105(12):4975-4986.
    PMID: 34146138 DOI: 10.1007/s00253-021-11226-w
    Marine microbes provide an important resource to discover new chemical compounds with biological activities beneficial to drug discovery. In our study, two new polyene macrolides, pyranpolyenolides A (1) and B (2), and one new natural cyclic peptide (9), together with two known polyenes (7 and 8) and three known cyclic peptides (10-12), were isolated from a culture of the marine Streptomyces sp. MS110128. In addition, four new polyene macrolides, pyranpolyenolides C-F (3-6), were identified as olefin geometric isomers that were most likely produced by photochemical conversion during the cultivation or isolation procedures. The pyranpolyenolides are 32-membered macrolides endowed with a conjugated tetraene and several pairs of 1,3-dihydroxyl groups. Pyranpolyenolides that contain a hydropyran group have not been previously reported. Four cyclic peptides (9-12) showed significant activities against Bacillus subtilis, Staphylococcus aureus, and methicillin-resistant S. aureus with supporting MIC values ranging from 0.025 to 1.25 μg/mL. These cyclic peptides containing piperazic moieties showed moderate activities with MIC values of 12.5 μg/mL against Bacille Calmette Guerin (BCG), an attenuated form of the bovine. Additionally, cyclic peptide 12 showed moderate antifungal activity against Candida albicans with an MIC value of 12.5 μg/mL. KEY POINTS: • Discovery of new polyenes and cyclic peptides from a marine-derived Actinomycete. • Cyclic peptides containing piperazic moieties exhibited good antibacterial activity.
  5. Swamy MK, Sinniah UR, Ghasemzadeh A
    Appl Microbiol Biotechnol, 2018 Sep;102(18):7775-7793.
    PMID: 30022261 DOI: 10.1007/s00253-018-9223-y
    Rosmarinic acid (RA) is a highly valued natural phenolic compound that is very commonly found in plants of the families Lamiaceae and Boraginaceae, including Coleus blumei, Heliotropium foertherianum, Rosmarinus officinalis, Perilla frutescens, and Salvia officinalis. RA is also found in other members of higher plant families and in some fern and horned liverwort species. The biosynthesis of RA is catalyzed by the enzymes phenylalanine ammonia lyase and cytochrome P450-dependent hydroxylase using the amino acids tyrosine and phenylalanine. Chemically, RA can be produced via methods involving the esterification of 3,4-dihydroxyphenyllactic acid and caffeic acid. Some of the derivatives of RA include melitric acid, salvianolic acid, lithospermic acid, and yunnaneic acid. In plants, RA is known to have growth-promoting and defensive roles. Studies have elucidated the varied pharmacological potential of RA and its derived molecules, including anticancer, antiangiogenic, anti-inflammatory, antioxidant, and antimicrobial activities. The demand for RA is therefore, very high in the pharmaceutical industry, but this demand cannot be met by plants alone because RA content in plant organs is very low. Further, many plants that synthesize RA are under threat and near extinction owing to biodiversity loss caused by unscientific harvesting, over-collection, environmental changes, and other inherent features. Moreover, the chemical synthesis of RA is complicated and expensive. Alternative approaches using biotechnological methodologies could overcome these problems. This review provides the state of the art information on the chemistry, sources, and biosynthetic pathways of RA, as well as its anticancer properties against different cancer types. Biotechnological methods are also discussed for producing RA using plant cell, tissue, and organ cultures and hairy-root cultures using flasks and bioreactors. The recent developments and applications of the functional genomics approach and heterologous production of RA in microbes are also highlighted. This chapter will be of benefit to readers aiming to design studies on RA and its applicability as an anticancer agent.
  6. Puan SL, Erriah P, Baharudin MMA, Yahaya NM, Kamil WNIWA, Ali MSM, et al.
    Appl Microbiol Biotechnol, 2023 Sep;107(18):5569-5593.
    PMID: 37450018 DOI: 10.1007/s00253-023-12651-9
    Antibiotic resistance is a growing concern that is affecting public health globally. The search for alternative antimicrobial agents has become increasingly important. Antimicrobial peptides (AMPs) produced by Bacillus spp. have emerged as a promising alternative to antibiotics, due to their broad-spectrum antimicrobial activity against resistant pathogens. In this review, we provide an overview of Bacillus-derived AMPs, including their classification into ribosomal (bacteriocins) and non-ribosomal peptides (lipopeptides and polyketides). Additionally, we delve into the molecular mechanisms of AMP production and describe the key biosynthetic gene clusters involved. Despite their potential, the low yield of AMPs produced under normal laboratory conditions remains a challenge to large-scale production. This review thus concludes with a comprehensive summary of recent studies aimed at enhancing the productivity of Bacillus-derived AMPs. In addition to medium optimization and genetic manipulation, various molecular strategies have been explored to increase the production of recombinant antimicrobial peptides (AMPs). These include the selection of appropriate expression systems, the engineering of expression promoters, and metabolic engineering. Bacillus-derived AMPs offer great potential as alternative antimicrobial agents, and this review provides valuable insights on the strategies to enhance their production yield, which may have significant implications for combating antibiotic resistance. KEY POINTS: • Bacillus-derived AMP is a potential alternative therapy for resistant pathogens • Bacillus produces two main classes of AMPs: ribosomal and non-ribosomal peptides • AMP yield can be enhanced using culture optimization and molecular approaches.
  7. Masri A, Abdelnasir S, Anwar A, Iqbal J, Numan A, Jagadish P, et al.
    Appl Microbiol Biotechnol, 2021 Apr;105(8):3315-3325.
    PMID: 33797573 DOI: 10.1007/s00253-021-11221-1
    BACKGROUND: Conducting polymer based nanocomposites are known to be effective against pathogens. Herein, we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii).

    RESULTS: The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells.

    CONCLUSION: These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications.

    KEY POINTS: •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.

  8. Chan SK, Lim TS
    Appl Microbiol Biotechnol, 2019 Apr;103(7):2973-2984.
    PMID: 30805670 DOI: 10.1007/s00253-019-09669-3
    Microbial transglutaminase (mTGase) is commonly known in the food industry as meat glue due to its incredible ability to "glue" meat proteins together. Aside from being widely exploited in the meat processing industries, mTGase is also widely applied in other food and textile industries by catalysing the formation of isopeptide bonds between peptides or protein substrates. The advancement of technology has opened up new avenues for mTGase in the field of biomedical engineering. Efforts have been made to study the structural properties of mTGase in order to gain an in-depth understanding of the structure-function relationship. This review highlights the developments in mTGase engineering together with its role in biomedical applications including biomaterial fabrication for tissue engineering and biotherapeutics.
  9. Luthfi AAI, Manaf SFA, Illias RM, Harun S, Mohammad AW, Jahim JM
    Appl Microbiol Biotechnol, 2017 Apr;101(8):3055-3075.
    PMID: 28280869 DOI: 10.1007/s00253-017-8210-z
    Due to the world's dwindling energy supplies, greater thrust has been placed on the utilization of renewable resources for global succinate production. Exploration of such biotechnological route could be seen as an act of counterbalance to the continued fossil fuel dominance. Malaysia being a tropical country stands out among many other nations for its plenty of resources in the form of lignocellulosic biomass. To date, oil palm frond (OPF) contributes to the largest fraction of agricultural residues in Malaysia, while kenaf, a newly introduced fiber crop with relatively high growth rate, holds great potential for developing sustainable succinate production, apart from OPF. Utilization of non-food, inexhaustible, and low-cost derived biomass in the form of OPF and kenaf for bio-based succinate production remains largely untapped. Owing to the richness of carbohydrates in OPF and kenaf, bio-succinate commercialization using these sources appears as an attractive proposition for future sustainable developments. The aim of this paper was to review some research efforts in developing a biorefinery system based on OPF and kenaf as processing inputs. It presents the importance of the current progress in bio-succinate commercialization, in addition to describing the potential use of different succinate production hosts and various pretreatments-saccharifications under development for OPF and kenaf. Evaluations on the feasibility of OPF and kenaf as fermentation substrates are also discussed.
  10. Arshad ZI, Amid A, Yusof F, Jaswir I, Ahmad K, Loke SP
    Appl Microbiol Biotechnol, 2014 Sep;98(17):7283-97.
    PMID: 24965557 DOI: 10.1007/s00253-014-5889-y
    This review highlights the use of bromelain in various applications with up-to-date literature on the purification of bromelain from pineapple fruit and waste such as peel, core, crown, and leaves. Bromelain, a cysteine protease, has been exploited commercially in many applications in the food, beverage, tenderization, cosmetic, pharmaceutical, and textile industries. Researchers worldwide have been directing their interest to purification strategies by applying conventional and modern approaches, such as manipulating the pH, affinity, hydrophobicity, and temperature conditions in accord with the unique properties of bromelain. The amount of downstream processing will depend on its intended application in industries. The breakthrough of recombinant DNA technology has facilitated the large-scale production and purification of recombinant bromelain for novel applications in the future.
  11. Abdul Manaf SA, Mohamad Fuzi SFZ, Low KO, Hegde G, Abdul Manas NH, Md Illias R, et al.
    Appl Microbiol Biotechnol, 2021 Nov;105(21-22):8531-8544.
    PMID: 34611725 DOI: 10.1007/s00253-021-11616-0
    Carbon nanomaterials, due to their catalytic activity and high surface area, have potential as cell immobilization supports to increase the production of xylanase. Recombinant Kluyveromyces lactis used for xylanase production was integrated into a polymeric gel network with carbon nanomaterials. Carbon nanomaterials were pretreated before cell immobilization with hydrochloric acid (HCl) treatment and glutaraldehyde (GA) crosslinking, which contributes to cell immobilization performance. Carbon nanotubes (CNTs) and graphene oxide (GO) were further screened using a Plackett-Burman experimental design. Cell loading and agar concentration were the most important factors in xylanase production with low cell leakage. Under optimized conditions, xylanase production was increased by more than 400% compared to free cells. Immobilized cell material containing such high cell densities may exhibit new and unexplored beneficial properties because the cells comprise a large fraction of the component. The use of carbon nanomaterials as a cell immobilization support along with the entrapment method successfully enhances the production of xylanase, providing a new route to improved bioprocessing, particularly for the production of enzymes. KEY POINTS: • Carbon nanomaterials (CNTs, GO) have potential as cell immobilization supports. • Entrapment in a polymeric gel network provides space for xylanase production. • Plackett-Burman design screen for the most important factor for cell immobilization.
  12. Raha AR, Varma NR, Yusoff K, Ross E, Foo HL
    Appl Microbiol Biotechnol, 2005 Jul;68(1):75-81.
    PMID: 15635459
    The food-grade Lactococcus lactis is a potential vector to be used as a live vehicle for the delivery of heterologous proteins for vaccine and pharmaceutical purposes. We constructed a plasmid vector pSVac that harbors a 255-bp single-repeat sequence of the cell wall-binding protein region of the AcmA protein. The recombinant plasmid was transformed into Escherichia coli and expression of the gene fragment was driven by the T7 promoter of the plasmid. SDS-PAGE showed the presence of the putative AcmA' fragment and this was confirmed by Western blot analysis. The protein was isolated and purified using a His-tag affinity column. When mixed with a culture of L. lactis MG1363, ELISA and immunofluorescence assays showed that the cell wall-binding fragment was anchored onto the outer surface of the bacteria. This indicated that the AcmA' repeat unit retained the active site for binding onto the cell wall surface of the L. lactis cells. Stability assays showed that the fusion proteins (AcmA/A1, AcmA/A3) were stably docked onto the surface for at least 5 days. The AcmA' fragment was also shown to be able to strongly bind onto the cell surface of naturally occurring lactococcal strains and Lactobacillus and, with less strength, the cell surface of Bacillus sphericus. The new system designed for cell surface display of recombinant proteins on L. lactis was evaluated for the expression and display of A1 and A3 regions of the VP1 protein of enterovirus 71 (EV71). The A1 and A3 regions of the VP1 protein of EV71 were cloned upstream to the cell wall-binding domains of AcmA protein and successfully expressed as AcmA/A1 and AcmA/A3. Whole-cell ELISA showed the successful display of VP1 protein epitopes of EV71 on the surface of L. lactis. The success of the anchoring system developed in this study for docking the A1 and A3 epitopes of VP1 onto the surface of L. lactis cells opens up the possibilities of peptide and protein display for not only Lactococcus but also for other gram-positive bacteria. This novel way of displaying epitopes on the cell surface of L. lactis and other related organisms should be very useful in the delivery of vaccines and other useful proteins.
  13. Gopinath SC, Lakshmipriya T, Chen Y, Arshad MK, Kerishnan JP, Ruslinda AR, et al.
    Appl Microbiol Biotechnol, 2016 Aug;100(16):6955-69.
    PMID: 27350620 DOI: 10.1007/s00253-016-7686-2
    Aptamers are single-stranded nucleic acids or peptides identified from a randomized combinatorial library through specific interaction with the target of interest. Targets can be of any size, from small molecules to whole cells, attesting to the versatility of aptamers for binding a wide range of targets. Aptamers show drug properties that are analogous to antibodies, with high specificity and affinity to their target molecules. Aptamers can penetrate disease-causing microbial and mammalian cells. Generated aptamers that target surface biomarkers act as cell-targeting agents and intracellular delivery vehicles. Within this context, the "cell-internalizing aptamers" are widely investigated via the process of cell uptake with selective binding during in vivo systematic evolution of ligands by exponential enrichment (SELEX) or by cell-internalization SELEX, which targets cell surface antigens to be receptors. These internalizing aptamers are highly preferable for the localization and functional analyses of multiple targets. In this overview, we discuss the ways by which internalizing aptamers are generated and their successful applications. Furthermore, theranostic approaches featuring cell-internalized aptamers are discussed with the purpose of analyzing and diagnosing disease-causing pathogens.
  14. Kahar UM, Ng CL, Chan KG, Goh KM
    Appl Microbiol Biotechnol, 2016 Jul;100(14):6291-307.
    PMID: 27000839 DOI: 10.1007/s00253-016-7451-6
    Type I pullulanases are enzymes that specifically hydrolyse α-1,6 linkages in polysaccharides. This study reports the analyses of a novel type I pullulanase (PulASK) from Anoxybacillus sp. SK3-4. Purified PulASK (molecular mass of 80 kDa) was stable at pH 5.0-6.0 and was most active at pH 6.0. The optimum temperature for PulASK was 60 °C, and the enzyme was reasonably stable at this temperature. Pullulan was the preferred substrate for PulASK, with 89.90 % adsorbance efficiency (various other starches, 56.26-72.93 % efficiency). Similar to other type I pullulanases, maltotriose was formed on digestion of pullulan by PulASK. PulASK also reacted with β-limit dextrin, a sugar rich in short branches, and formed maltotriose, maltotetraose and maltopentaose. Nevertheless, PulASK was found to preferably debranch long branches at α-1,6 glycosidic bonds of starch, producing amylose, linear or branched oligosaccharides, but was nonreactive against short branches; thus, no reducing sugars were detected. This is surprising as all currently known type I pullulanases produce reducing sugars (predominantly maltotriose) on digesting starch. The closest homologue of PulASK (95 % identity) is a type I pullulanase from Anoxybacillus sp. LM14-2 (Pul-LM14-2), which is capable of forming reducing sugars from starch. With rational design, amino acids 362-370 of PulASK were replaced with the corresponding sequence of Pul-LM14-2. The mutant enzyme formed reducing sugars on digesting starch. Thus, we identified a novel motif involved in substrate specificity in type I pullulanases. Our characterization may pave the way for the industrial application of this unique enzyme.
  15. Watts MP, Spurr LP, Gan HM, Moreau JW
    Appl Microbiol Biotechnol, 2017 Jul;101(14):5889-5901.
    PMID: 28510801 DOI: 10.1007/s00253-017-8313-6
    Thiocyanate (SCN-) forms as a by-product of cyanidation during gold ore processing and can be degraded by a variety of microorganisms utilizing it as an energy, nitrogen, sulphur and/or carbon source. In complex consortia inhabiting bioreactor systems, a range of metabolisms are sustained by SCN- degradation; however, despite the addition or presence of labile carbon sources in most bioreactor designs to date, autotrophic bacteria have been found to dominate key metabolic functions. In this study, we cultured an autotrophic SCN--degrading consortium directly from gold mine tailings. In a batch-mode bioreactor experiment, this consortium degraded 22 mM SCN-, accumulating ammonium (NH4+) and sulphate (SO42-) as the major end products. The consortium consisted of a diverse microbial community comprised of chemolithoautotrophic members, and despite the absence of an added organic carbon substrate, a significant population of heterotrophic bacteria. The role of eukaryotes in bioreactor systems is often poorly understood; however, we found their 18S rRNA genes to be most closely related to sequences from bacterivorous Amoebozoa. Through combined chemical and phylogenetic analyses, we were able to infer roles for key microbial consortium members during SCN- biodegradation. This study provides a basis for understanding the behaviour of a SCN- degrading bioreactor under autotrophic conditions, an anticipated approach to remediating SCN- at contemporary gold mines.
  16. Jamek SB, Nyffenegger C, Muschiol J, Holck J, Meyer AS, Mikkelsen JD
    Appl Microbiol Biotechnol, 2017 Jun;101(11):4533-4546.
    PMID: 28280871 DOI: 10.1007/s00253-017-8198-4
    Type A chitinases (EC 3.2.1.14), GH family 18, attack chitin ((1 → 4)-2-acetamido-2-deoxy-β-D-glucan) and chito-oligosaccharides from the reducing end to catalyze release of chitobiose (N,N'-diacetylchitobiose) via hydrolytic cleavage of N-acetyl-β-D-glucosaminide (1 → 4)-β-linkages and are thus "exo-chitobiose hydrolases." In this study, the chitinase type A from Serratia marcescens (SmaChiA) was used as a template for identifying two novel exo-chitobiose hydrolase type A enzymes, FbalChi18A and MvarChi18A, originating from the marine organisms Ferrimonas balearica and Microbulbifer variabilis, respectively. Both FbalChi18A and MvarChi18A were recombinantly expressed in Escherichia coli and were confirmed to exert exo-chitobiose hydrolase activity on chito-oligosaccharides, but differed in temperature and pH activity response profiles. Amino acid sequence comparison of the catalytic β/α barrel domain of each of the new enzymes showed individual differences, but ~69% identity of each to that of SmaChiA and highly conserved active site residues. Superposition of a model substrate on 3D structural models of the catalytic domain of the enzymes corroborated exo-chitobiose hydrolase type A activity for FbalChi18A and MvarChi18A, i.e., substrate attack from the reducing end. A main feature of both of the new enzymes was the presence of C-terminal 5/12 type carbohydrate-binding modules (SmaChiA has no C-terminal carbohydrate binding module). These new enzymes may be useful tools for utilization of chitin as an N-acetylglucosamine donor substrate via chitobiose.
  17. Abd Razak DL, Abdullah N, Khir Johari NM, Sabaratnam V
    Appl Microbiol Biotechnol, 2013 Apr;97(7):3207-13.
    PMID: 22576946 DOI: 10.1007/s00253-012-4135-8
    The potential for using agricultural and industrial by-products as substrate for the production of the edible mushroom, Auricularia polytricha, was evaluated using several formulations of selected palm oil wastes mixed with sawdust and further supplemented with selected nitrogen sources. The best substrate formulations were sawdust (SD) mixed with oil palm frond (OPF; 90:10) added with 15% spent grain (SG) and sawdust mixed with empty fruit bunch (EFB; 50:50) added with 10% spent grain (SG) with mycelia growth rate of 8 mm/day and 7 mm/day respectively. These two substrate formulations were then subjected to different moisture content levels (65%, 75% and 85%). Highest total fresh sporophore yield at 0.43% was obtained on SD+OPF (90:10)+15% SG at 85% moisture content, followed closely by SD+EFB (50:50)+10% SG with 0.40% total yield, also at 85% moisture content. Each of the substrate formulations at 85% moisture content gave the highest biological efficiency (BE) at 288.9% and 260.7%, respectively. Both yield and biological efficiency of A. polytricha on these two formulations were almost three times higher when compared to sawdust substrate alone, thus proving the potential of these formulations to improve yield of this mushroom.
  18. Teh AH, Fazli NH, Furusawa G
    Appl Microbiol Biotechnol, 2020 Jan;104(2):633-641.
    PMID: 31784792 DOI: 10.1007/s00253-019-10237-y
    PdAgaC from the marine bacterium Persicobacter sp. CCB-QB2 is a β-agarase belonging to the glycoside hydrolase family 16 (GH16). It is one of only a handful of endo-acting GH16 β-agarases able to degrade agar completely to produce neoagarobiose (NA2). The crystal structure of PdAgaC's catalytic domain, which has one of the highest Vmax value at 2.9 × 103 U/mg, was determined in order to understand its unique mechanism. The catalytic domain is made up of a typical β-jelly roll fold with two additional insertions, and a well-conserved but wider substrate-binding cleft with some minor changes. Among the unique differences, two unconserved residues, Asn226 and Arg286, may potentially contribute additional hydrogen bonds to subsites -1 and +2, respectively, while a third, His185 from one of the additional insertions, may further contribute another bond to subsite +2. These additional hydrogen bonds may probably have enhanced PdAgaC's affinity for short agaro-oligosaccharides such as neoagarotetraose (NA4), rendering it capable of binding NA4 strongly enough for rapid degradation into NA2.
  19. Ayoib A, Hashim U, Gopinath SCB, Md Arshad MK
    Appl Microbiol Biotechnol, 2017 Nov;101(22):8077-8088.
    PMID: 28942548 DOI: 10.1007/s00253-017-8493-0
    This review covers a developmental progression on early to modern taxonomy at cellular level following the advent of electron microscopy and the advancement in deoxyribonucleic acid (DNA) extraction for expatiation of biological classification at DNA level. Here, we discuss the fundamental values of conventional chemical methods of DNA extraction using liquid/liquid extraction (LLE) followed by development of solid-phase extraction (SPE) methods, as well as recent advances in microfluidics device-based system for DNA extraction on-chip. We also discuss the importance of DNA extraction as well as the advantages over conventional chemical methods, and how Lab-on-a-Chip (LOC) system plays a crucial role for the future achievements.
  20. Nittami T, Mukai M, Uematsu K, Yoon LW, Schroeder S, Chua ASM, et al.
    Appl Microbiol Biotechnol, 2017 Dec;101(23-24):8607-8619.
    PMID: 29063174 DOI: 10.1007/s00253-017-8571-3
    Previous studies have shown that enhanced biological phosphorus removal (EBPR) performance under continuous aerobic conditions always eventually deteriorates; however, the speed at which this happens depends on the carbon source supplied. The published data suggest that propionate is a better carbon source than acetate is for maintaining operational stability, although it is not clear why. A lab-scale sequencing batch reactor was run initially under conventional anaerobic/aerobic conditions with either acetate or propionate as the carbon source. Chemical and microbiological analyses revealed that both sources performed as expected for such systems. When continuous aerobic conditions were imposed on both these established communities, marked shifts of the "Candidatus Accumulibacter" clades were recorded for both carbon sources. Here, we discuss whether this shift could explain the prolonged EBPR stability observed with propionate.
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