Displaying publications 101 - 120 of 488 in total

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  1. Fulltext The influence of agitation on oil substrate dispersion and oxygen transfer in Pseudomonas aeruginosa USM-AR2 fermentation producing rhamnolipid in a stirred tank bioreactor
    Nur Asshifa MN, Zambry NS, Salwa MS, Yahya ARM
    3 Biotech, 2017 Jul;7(3):189.
    PMID: 28664380 DOI: 10.1007/s13205-017-0828-0
    Water-immiscible substrate, diesel, was supplied as the main substrate in the fermentation of Pseudomonas aeruginosa USM-AR2 producing rhamnolipid biosurfactant, in a stirred tank bioreactor. In addition to the typical gas-aqueous system, this system includes gas-hydrocarbon-aqueous phases and the presence of surfactant (rhamnolipid) in the fermentation broth. The effect of diesel dispersion on volumetric oxygen transfer coefficient, k L a, and thus oxygen transfer, was evaluated at different agitations of 400, 500 and 600 rpm. The oxygen transfer in this oil-water-surfactant system was shown to be affected by different oil dispersion at those agitation rates. The highest diesel dispersion was obtained at 500 rpm or impeller tip speed of 1.31 m/s, compared to 400 and 600 rpm, which led to the highest k L a, growth and rhamnolipid production by P. aeruginosa USM-AR2. This showed the highest substrate mixing and homogenization at this agitation speed that led to the efficient substrate utilization by the cells. The oxygen uptake rate of P. aeruginosa USM-AR2 was 5.55 mmol/L/h, which showed that even the lowest k L a (48.21 h-1) and hence OTR (57.71 mmol/L/h) obtained at 400 rpm was sufficient to fulfill the oxygen demand of the cells. The effect of rhamnolipid concentration on k L a showed that k L a increased as rhamnolipid concentration increased to 0.6 g/L before reaching a plateau. This trend was similar for all agitation rates of 400, 500 and 600 rpm, which might be due to the increase in the resistance to oxygen transfer (k L decrease) and the increase in the specific interfacial area (a).
    Matched MeSH terms: Fermentation
  2. Fulltext Antioxidant Properties of Crude Extract, Partition Extract, and Fermented Medium of Dendrobium sabin Flower
    Abu F, Mat Taib CN, Mohd Moklas MA, Mohd Akhir S
    Evid Based Complement Alternat Med, 2017;2017:2907219.
    PMID: 28761496 DOI: 10.1155/2017/2907219
    Antioxidant properties of crude extract, partition extract, and fermented medium from Dendrobium sabin (DS) flower were investigated. The oven-dried DS flower was extracted using 100% methanol (w/v), 100% ethanol (w/v), and 100% water (w/v). The 100% methanolic crude extract showed the highest total phenolic content (40.33 ± mg GAE/g extract) and the best antioxidant properties as shown by DPPH, ABTS, and FRAP assays. A correlation relationship between antioxidant activity and total phenolic content showed that phenolic compounds were the dominant antioxidant components in this flower extract. The microbial fermentation on DS flower medium showed a potential in increasing the phenolic content and DPPH scavenging activity. The TPC of final fermented medium showed approximately 18% increment, while the DPPH of fermented medium increased significantly to approximately 80% at the end of the fermentation. Dendrobium sabin (DS) flower showed very good potential properties of antioxidant in crude extract and partition extract as well as better antioxidant activity in the flower fermented medium.
    Matched MeSH terms: Fermentation
  3. Oil palm fiber biodegradation: physico-chemical and structural relationships
    Omar FN, Hafid HS, Samsu Baharuddin A, Mohammed MAP, Abdullah J
    Planta, 2017 Sep;246(3):567-577.
    PMID: 28620814 DOI: 10.1007/s00425-017-2717-5
    MAIN CONCLUSION: X-ray microtomography results revealed that delignification process damaged the oil palm fibers, which correlated well with reduction of lignin components and increase of the phenolic content. Biodegradation investigation of natural fibers normally focuses on physico-chemical analysis, with less emphasis on physical aspect like fiber structures affect from microbial activity. In this work, the performance of Pycnoporus sanguineus to delignify oil palm empty fruit bunch fibers through solid-state fermentation utilizing various ratio of POME sludge was reported. In addition to tensile testing, physico-chemical and X-ray microtomography (µ-CT) analyses on the oil palm fibers were conducted to determine the effectiveness of the degradation process. The best ratio of fiber to fungi (60:40) was chosen based on the highest lignin loss and total phenolic content values and further investigation was performed to obtain fermentation kinetics data of both laccase and manganese peroxidase. µ-CT results revealed that delignification process damaged the pre-treated and untreated fibers structure, as evident from volume reduction after degradation process. This is correlated with reduction of lignin component and increase of the phenolic content, as well as lower stress-strain curves of the pre-treated fibers compared to the untreated ones (from tensile testing). It is suggested that P. sanguineus preferred to consume the outer layer of the fiber, before it penetrates through the cellular structure of the inner fiber.
    Matched MeSH terms: Fermentation
  4. Aroma profile of a traditionally fermented butter (smen)
    Iradukunda C, Aida WMW, Ouafi AT, Barkouch Y, Boussaid A
    J Dairy Res, 2018 Feb;85(1):114-120.
    PMID: 29468995 DOI: 10.1017/S0022029917000796
    Matched MeSH terms: Fermentation
  5. Fulltext Impact of pH and butyric acid on butanol production during batch fermentation using a new local isolate of Clostridium acetobutylicum YM1
    Al-Shorgani NKN, Kalil MS, Yusoff WMW, Hamid AA
    Saudi J Biol Sci, 2018 Feb;25(2):339-348.
    PMID: 29472788 DOI: 10.1016/j.sjbs.2017.03.020
    The effect of pH and butyric acid supplementation on the production of butanol by a new local isolate of Clostridium acetobutylicum YM1 during batch culture fermentation was investigated. The results showed that pH had a significant effect on bacterial growth and butanol yield and productivity. The optimal initial pH that maximized butanol production was pH 6.0 ± 0.2. Controlled pH was found to be unsuitable for butanol production in strain YM1, while the uncontrolled pH condition with an initial pH of 6.0 ± 0.2 was suitable for bacterial growth, butanol yield and productivity. The maximum butanol concentration of 13.5 ± 1.42 g/L was obtained from cultures grown under the uncontrolled pH condition, resulting in a butanol yield (YP/
    S
    ) and productivity of 0.27 g/g and 0.188 g/L h, respectively. Supplementation of the pH-controlled cultures with 4.0 g/L butyric acid did not improve butanol production; however, supplementation of the uncontrolled pH cultures resulted in high butanol concentrations, yield and productivity (16.50 ± 0.8 g/L, 0.345 g/g and 0.163 g/L h, respectively). pH influenced the activity of NADH-dependent butanol dehydrogenase, with the highest activity obtained under the uncontrolled pH condition. This study revealed that pH is a very important factor in butanol fermentation by C. acetobutylicum YM1.
    Matched MeSH terms: Fermentation
  6. Fulltext The illustration of a rat large intestine: a model for the effect of Carcinogens
    Khodijah Zulkiflee, Zunariah Buyong, Asmah Hanim Hamdan
    International Medical Journal Malaysia, 2017;16(11):28-28.
    MyJurnal
    Rat large intestine is an established model to study the effect of
    carcinogens. There are several distinctive features among mammalian gastrointestinal
    tracts in gross anatomy but they share some basic similar structures. The variety in
    digestive system relies on its physiology. Rats rarely eat high fatty diets, thus the
    function of gall bladder become less significant in their digestive system and this is
    justified by the fact that rats have none. Rats have large caecum designated for their
    fermentation chamber to digest cellulose. Another notable difference is the size and
    length of colon itself, in which human colon is significantly bigger and longer. We aimed
    to demonstrate the gross anatomy and histology of rat digestive system particularly the
    large intestine. (Copied from article).
    Matched MeSH terms: Fermentation
  7. Fulltext Solid-state fermentation of oil palm frond petiole for lignin peroxidase and xylanase-rich cocktail production
    Mohamad Ikubar MR, Abdul Manan M, Md Salleh M, Yahya A
    3 Biotech, 2018 May;8(5):259.
    PMID: 29765817 DOI: 10.1007/s13205-018-1268-1
    In current practice, oil palm frond leaflets and stems are re-used for soil nutrient recycling, while the petioles are typically burned. Frond petioles have high commercialization value, attributed to high lignocellulose fiber content and abundant of juice containing free reducing sugars. Pressed petiole fiber is the subject of interest in this study for the production of lignocellulolytic enzyme. The initial characterization showed the combination of 0.125 mm frond particle size and 60% moisture content provided a surface area of 42.3 m2/g, porosity of 12.8%, and density of 1.2 g/cm3, which facilitated fungal solid-state fermentation. Among the several species of Aspergillus and Trichoderma tested, Aspergillus awamori MMS4 yielded the highest xylanase (109 IU/g) and cellulase (12 IU/g), while Trichoderma virens UKM1 yielded the highest lignin peroxidase (222 IU/g). Crude enzyme cocktail also contained various sugar residues, mainly glucose and xylose (0.1-0.4 g/L), from the hydrolysis of cellulose and hemicellulose. FT-IR analysis of the fermented petioles observed reduction in cellulose crystallinity (I900/1098), cellulose-lignin (I900/1511), and lignin-hemicellulose (I1511/1738) linkages. The study demonstrated successful bioconversion of chemically untreated frond petioles into lignin peroxidase and xylanase-rich enzyme cocktail under SSF condition.
    Matched MeSH terms: Fermentation
  8. 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: Fermentation
  9. Fulltext Bioconversion of Leachate to Acetic and Butyric acid by Clostridium butyricum NCIMB 7423 in membrane fermentor
    Othman, M.F., Tamat, M.R., Wan Nadiah, W.A., Serri, N.A., Aziz, H.A., Tajarudin, H.A.
    Pertanika Journal of Science & Technology, 2017;25(108):39-48.
    MyJurnal
    Landfill leachate imposes a huge problem to the environment and human beings. This work focused on bioconversion of leachate to acetic and butyric acids by Clostridium butyricum NCIMB 7423. A continuous stirred tank reactor (CSTR) was applied and connected to fabricate membrane module. The leachate was collected from Pulau Burung Landfill Site (PBLS), Nibong Tebal, Penang. Prior to fermentation, leachate was treated to remove volatile fatty acid and adjusted to meet the minimum requirement of nutrients for anaerobic fermentation. Synthetic medium fermentation acts as a benchmark to the leachate fermentation. The outcomes indicated that the yield of acetic acid and butyric acid in synthetic medium fermentation was 0.70 g/L and 0.71 g/L, respectively. Meanwhile, leachate fermentation showed that the yield of acetic and butyric acid was 0.93 g/L and 1.86 g/L, respectively. High production of acetic and butyric acid showed that leachate fermentation is a green alternative to produce a cleaner product.
    Matched MeSH terms: Fermentation
  10. Fulltext Simulation and optimisation of Bioethanol purification using extractive distillation with additive solvent
    Anisuzzaman, S.M., Krishnaiah, D., Bono, A., Lahin, F.A., Suali, E., Zuyyin, I.A.Z.
    Pertanika Journal of Science & Technology, 2018;26(2):707-718.
    MyJurnal
    In this study, simulation and optimisation of the purification of bioethanol from an azeotropic mixture was done using the Aspen HYSYS and the Response Surface Methodology (RSM), respectively, to achieve an acceptable bioethanol content with minimal energy use. The objective of this study is to develop the simulation process of bioethanol production from a fermentation effluent. Additionally, the effects of parameters such as solvent temperature, number of entrainer feed stage, mass flow rate and third components of the process for production of bioethanol were studied. As bioethanol is a product of biofuel production, the main challenge facing bioethanol production is the separation of high purity ethanol. However, the separation of ethanol and water can be achieved with the addition of a suitable solvent such as 1,3-butylene glycol (13C4Diol), mixture 13C4Diol and ethylene glycol (EGlycol) and mixture 13C4Diol and glycol ethyl ether (DEG) in the extractive distillation process. For the 13C4Diol mixture, the temperature of entrainer is 90oC with 1500 kg/hr of entrainer rate, while the number of entrainer feed stage is one. The optimum conditions for mixture 13C4Diol and EGlycol require a temperature of entrainer of 90.77oC with an entrainer rate of 1500 kg/hr, while the number of entrainer feed stage is one. Lastly, for optimum conditions for the mixture 13C4Diol and DEG, the temperature of entrainer should be 90oC with an entrainer rate of 1564.04 kg/hr, while the number of entrainer feed stage is one. This study shows that process simulation and optimisation can enhance the removal of water from an azeotropic mixture.
    Matched MeSH terms: Fermentation
  11. Determination of optimum harvest maturity and non-destructive evaluation of pod development and maturity in cacao (Theobroma cacao L.) using a multiparametric fluorescence sensor
    Tee YK, Balasundram SK, Ding P, M Hanif AH, Bariah K
    J Sci Food Agric, 2019 Mar 15;99(4):1700-1708.
    PMID: 30206959 DOI: 10.1002/jsfa.9359
    BACKGROUND: A series of fluorescence indices (anthocyanin, flavonol, chlorophyll and nitrogen balance) were deployed to detect the pigments and colourless flavonoids in cacao pods of three commercial cacao (Theobroma cacao L.) genotypes (QH1003, KKM22 and MCBC1) using a fast and non-destructive multiparametric fluorescence sensor. The aim was to determine optimum harvest periods (either 4 or 5 months after pod emergence) of commercial cacao based on fluorescence indices of cacao development and bean quality.

    RESULTS: As pod developed, cacao exhibited a rise with the peak of flavonol occurring at months 4 and 5 after pod maturity was initiated while nitrogen balance showed a decreasing trend during maturity. Cacao pods contained high chlorophyll as they developed but chlorophyll content declined significantly on pods that ripened at month 5.

    CONCLUSION: Cacao pods harvested at months 4 and 5 can be considered as commercially-ready as the beans have developed good quality and comply with the Malaysian standard on cacao bean specification. Thus, cacao pods can be harvested earlier when they reach maturity at month 4 after pod emergence to avoid germinated beans and over fermentation in ripe pods harvested at month 5. © 2018 Society of Chemical Industry.

    Matched MeSH terms: Fermentation
  12. Physicochemical properties and toxicity of cocoa powder-like product from roasted seeds of fermented rambutan (Nephelium lappaceum L.) fruit
    Chai KF, Chang LS, Adzahan NM, Karim R, Rukayadi Y, Ghazali HM
    Food Chem, 2019 Jan 15;271:298-308.
    PMID: 30236681 DOI: 10.1016/j.foodchem.2018.07.155
    A novel way to fully utilize rambutan fruit and seed is to ferment peeled fruits followed by drying and roasting, and use the seeds to produce seed powder similar to that of cocoa powder. Hence, the objective of this study was to optimize the roasting time and temperature of rambutan fruit post-fermentation and drying, and to produce a cocoa-like powder product from the seeds. Parameters monitored during roasting were colour and total phenolic content, while seed powder obtained using optimized roasting conditions was analyzed for its physicochemical properties and toxicity. The latter was examined using the brine shrimp lethality assay. Results showed that the roasted seed powder possessed colour and key volatile compounds similar to that of cocoa powder. Besides, the brine shrimp lethality assay indicated that the roasted seed powder was non-toxic. Thus, the fruit, including its seed could be fully utilized and subsequently, wastage could be reduced.
    Matched MeSH terms: Fermentation
  13. Fulltext Evaluation of a Malaysian soy sauce koji strain Aspergillus oryzae NSK for γ-aminobutyric acid (GABA) production using different native sugars
    Hajar-Azhari S, Wan-Mohtar WAAQI, Ab Kadir S, Rahim MHA, Saari N
    Food Sci Biotechnol, 2018 Apr;27(2):479-488.
    PMID: 30263772 DOI: 10.1007/s10068-017-0289-6
    In this study, a selected γ-aminobutyric acid (GABA)-rich Malaysian strain Aspergillus oryzae NSK was collected from soy sauce koji. The strain was used to explore the effect of using renewable native sugar syrup, sugarcane, nipa, and molasses as fermentable substrates for developing a novel functional GABA soy sauce. We evaluated the strain using the chosen native sugars for 7 days using shake flask fermentation at 30 °C. The results showed optimum GABA concentration was achieved using cane molasses as the fermentable substrate (354.08 mg/L), followed by sugarcane syrup (320.7 mg/L) and nipa syrup (232.07 mg/L). Cane molasses was subsequently utilized as a substrate to determine the most suitable concentration for A. oryzae NSK to enhance GABA production and was determined as 50% g/L of glucose standard cane molasses. Our findings indicate that cane molasses can be used as a GABA-rich ingredient to develop a new starter culture for A. oryzae NSK soy sauce production.
    Matched MeSH terms: Fermentation
  14. Fulltext Optimisation of Simultaneous Saccharification and Fermentation (SSF) for Biobutanol Production Using Pretreated Oil Palm Empty Fruit Bunch
    Md Razali NAA, Ibrahim MF, Kamal Bahrin E, Abd-Aziz S
    Molecules, 2018 Aug 03;23(8).
    PMID: 30081514 DOI: 10.3390/molecules23081944
    This study was conducted in order to optimise simultaneous saccharification and fermentation (SSF) for biobutanol production from a pretreated oil palm empty fruit bunch (OPEFB) by Clostridium acetobutylicum ATCC 824. Temperature, initial pH, cellulase loading and substrate concentration were screened using one factor at a time (OFAT) and further statistically optimised by central composite design (CCD) using the response surface methodology (RSM) approach. Approximately 2.47 g/L of biobutanol concentration and 0.10 g/g of biobutanol yield were obtained after being screened through OFAT with 29.55% increment (1.42 fold). The optimised conditions for SSF after CCD were: temperature of 35 °C, initial pH of 5.5, cellulase loading of 15 FPU/g-substrate and substrate concentration of 5% (w/v). This optimisation study resulted in 55.95% increment (2.14 fold) of biobutanol concentration equivalent to 3.97 g/L and biobutanol yield of 0.16 g/g. The model and optimisation design obtained from this study are important for further improvement of biobutanol production, especially in consolidated bioprocessing technology.
    Matched MeSH terms: Fermentation
  15. Fulltext Bioethanol production from agarophyte red seaweed, Gelidium elegans, using a novel sample preparation method for analysing bioethanol content by gas chromatography
    Hessami MJ, Cheng SF, Ambati RR, Yin YH, Phang SM
    3 Biotech, 2019 Jan;9(1):25.
    PMID: 30622863 DOI: 10.1007/s13205-018-1549-8
    In this study, Gelidium elegans is investigated for ethanol production. A combination of factors including different temperatures, acid concentration and incubation time was evaluated to determine the suitable saccharification conditions. The combination of 2.5% (w/v) H2SO4 at 120 °C for 40 min was selected for hydrolysis of the seaweed biomass, followed by purification, and fermentation to yield ethanol. The galactose and glucose were dominant reducing sugars in the G. elegans hydrolysate and under optimum condition of dilute acid hydrolysis, 39.42% of reducing sugars was produced and fermentation resulted in ethanol concentration of 13.27 ± 0.47 g/L. A modified method was evaluated for sample preparation for gas chromatography (GC) analysis of the ethanol content. A solvent mixture of acetonitrile and iso-butanol precipitated dissolved organic residues and reduced water content in GC samples at least by 90%. Results showed that this method could be successfully used for bioethanol production from seaweed.
    Matched MeSH terms: Fermentation
  16. Lipid production by Lipomyces starkeyi using sap squeezed from felled old oil palm trunks
    Juanssilfero AB, Kahar P, Amza RL, Yopi, Sudesh K, Ogino C, et al.
    J Biosci Bioeng, 2019 Jun;127(6):726-731.
    PMID: 30642786 DOI: 10.1016/j.jbiosc.2018.12.002
    The ability of oleaginous yeast Lipomyces starkeyi to efficiently produce lipids when cultivated on sap extracted from felled oil palm trunk (OPT) as a novel inexpensive renewable carbon source was evaluated. OPT sap was found to contain approximately 98 g/L glucose and 32 g/L fructose. Batch fermentations were performed using three different OPT sap medium conditions: regular sap, enriched sap, and enriched sap at pH 5.0. Under all sap medium conditions, the cell biomass and lipid production achieved were approximately 30 g/L and 60% (w/w), respectively. L. starkeyi tolerated acidified medium (initial pH ≈ 3) and produced considerable amounts of ethanol as well as xylitol as by-products. The fatty acid profile of L. starkeyi was remarkably similar to that of palm oil, one of the most common vegetable oil feedstock used in biodiesel production with oleic acid as the major fatty acid followed by palmitic, stearic and linoleic acids.
    Matched MeSH terms: Fermentation
  17. Application of thermo-separating aqueous two-phase system in extractive bioconversion of polyhydroxyalkanoates by Cupriavidus necator H16
    Leong YK, Show PL, Lan JC, Krishnamoorthy R, Chu DT, Nagarajan D, et al.
    Bioresour Technol, 2019 Sep;287:121474.
    PMID: 31122870 DOI: 10.1016/j.biortech.2019.121474
    Polyhydroxyalkanoates (PHAs), a family of biodegradable and renewable biopolymers show a huge potential as an alternative to conventional plastics. Extractive bioconversion (in situ product recovery) is a technique that integrates upstream fermentation and downstream purification. In this study, extractive bioconversion of PHAs from Cupriavidus necator H16 was performed via a thermo-separating aqueous two-phase system to reduce the cost and environmental impacts of PHAs production. Key operating parameters, such as polymer concentration, temperature, and pH, were optimized. The strategy achieved a yield and PF of 97.6% and 1.36-fold, respectively at 5% EOPO 3900 concentration, 30 °C fermentation temperature and pH 6. The PHAs production process was also successfully scaled up in a 2 L bioreactor. To the best of our knowledge, this is the first report on extractive fermentation of PHAs from Cupriavidus necator utilizing a thermo-separation system to achieve a better productivity and purity of the target product.
    Matched MeSH terms: Fermentation
  18. Solvent fermentation from Palm Oil Mill Effluent using Clostridium acetobutylicum in oscillatory flow bioreactor
    Takriff M, Masngut N, Kadhum A, Kalil M, Mohammad A
    Sains Malaysiana, 2009;38.
    Acetone-butanol-ethanol (ABE) fermentation from Palm Oil Mill Effluent (POME) by C. acetobutylicum NCIMB 13357 in an oscillatory flow bioreactor was investigated. Experimental works were conducted in a U-shaped stainless steel oscillatory flow bioreactor at oscillation frequency between 0.45-0.78 Hz and a constant amplitude of 12.5 mm. Fermentations were carried out for 72 hr at 35oC using palm oil mill effluent and reinforced clostridia medium as a growth medium in batch culture. Result of this investigation showed that POME is a viable media for ABE fermentation and oscillatory flow bioreactor has an excellent potential as an alternative fermentation device.
    Matched MeSH terms: Fermentation
  19. Pilot test of a fermentation tank for producing coal methane through anaerobic fermentation
    Daping Xia, Huaiwen Zhang, Xile Liu, Chaoyong Fu, Xianbo Su
    Sains Malaysiana, 2017;46:2083-2089.
    The development and utilization of clean energy has long been a focus of research. In the coal bed methane field, most coal bed biogenic methane experiments are small static sample tests in which the initial conditions are set and the process cannot be batch-fed elements and microbial strains, and the gas cannot be collected in batches. Although significant results have been achieved in the coal-to-biogenic methane conversion in China, findings are restricted to the laboratory scale. No successful commercialization of coal bed biogenic methane production has been achieved yet. This study used a large-capacity fermentation tank (5 L) to conduct biogenic methane experiments. Results were compared to those from the traditional laboratory test. The gas production rate and gas concentration were higher when the 250 mL methane test volume was increased to a 5 L fermentation volume, increasing by 20.9% and 2.3%, respectively. The inhibition effect of the liquid phase products was reduced in the large fermentation tank, and the microbial activity was extended by batch feeding trace elements (iron and nickel) and methane strains and by semi-continuous collection of the gas. However, the gas conversion rate can be increased by retaining the H2 and CO2 in the intermediate gas products in the fermentation tank. The gas production rate was increased from 17.9 to 24.6 mL/g, increasing by 37.4%. The simulation pilot test can lay a foundation for the transition from a coal bed biogenic methane laboratory static small sample test to a dynamic pilot test, optimizing the process parameters to improve the reaction efficiency and move forward to commercialization test.
    Matched MeSH terms: Fermentation
  20. Ethanol production capability of Candida shehatae in mixed sugars and rice straw hydrolysate
    Yuvadetkun P, Boonmee M
    Sains Malaysiana, 2016;45:581-587.
    Ethanol fermentations by Candida shehatae TISTR 5843 at low (20 g/L) and high (80 g/L) sugar concentrations with various glucose to xylose ratios were investigated. Glucose was a preferred substrate as it was consumed first at a faster consumption rate. The type of sugar and ratio between glucose and xylose did not have an effect on ethanol produced. The average ethanol concentrations were 7.99 g/L when using 20 g/L sugar and 27.82 g/L when using 80 g/L sugar. Small amounts of xylitol and glycerol as by-products were presented when using 20 g/L sugar. Xylitol appeared to be the main by-product at high xylose concentration with elevated concentrations as xylose is increased. When using rice straw hydrolysate containing 34.75 g/L glucose and 21.29 g/L xylose, 19.37 g/L ethanol was produced with the ethanol yield and ethanol productivity at 0.49 g/g and 0.20 g/L.h, respectively. However, xylose was not completely consumed after fermentation was complete.
    Matched MeSH terms: Fermentation
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