Displaying publications 1 - 20 of 58 in total

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  1. Short Chain Fatty Acids: Fundamental mediators of the gut-lung axis and their involvement in pulmonary diseases
    Ashique S, De Rubis G, Sirohi E, Mishra N, Rihan M, Garg A, et al.
    Chem Biol Interact, 2022 Dec 01;368:110231.
    PMID: 36288778 DOI: 10.1016/j.cbi.2022.110231
    The human microbiota is fundamental to correct immune system development and balance. Dysbiosis, or microbial content alteration in the gut and respiratory tract, is associated with immune system dysfunction and lung disease development. The microbiota's influence on human health and disease is exerted through the abundance of metabolites produced by resident microorganisms, where short-chain fatty acids (SCFAs) represent the fundamental class. SCFAs are mainly produced by the gut microbiota through anaerobic fermentation of dietary fibers, and are known to influence the homeostasis, susceptibility to and outcome of many lung diseases. This article explores the microbial species found in healthy human gastrointestinal and respiratory tracts. We investigate factors contributing to dysbiosis in lung illness, and the gut-lung axis and its association with lung diseases, with a particular focus on the functions and mechanistic roles of SCFAs in these processes. The key focus of this review is a discussion of the main metabolites of the intestinal microbiota that contribute to host-pathogen interactions: SCFAs, which are formed by anaerobic fermentation. These metabolites include propionate, acetate, and butyrate, and are crucial for the preservation of immune homeostasis. Evidence suggests that SCFAs prevent infections by directly affecting host immune signaling. This review covers the various and intricate ways through which SCFAs affect the immune system's response to infections, with a focus on pulmonary diseases including chronic obstructive pulmonary diseases, asthma, lung cystic fibrosis, and tuberculosis. The findings reviewed suggest that the immunological state of the lung may be indirectly influenced by elements produced by the gut microbiota. SCFAs represent valuable potential therapeutic candidates in this context.
    Matched MeSH terms: Fatty Acids, Volatile/metabolism; Fatty Acids, Volatile/therapeutic use
  2. Aerobic dynamic feeding as a strategy for in situ accumulation of polyhydroxyalkanoate in aerobic granules
    Gobi K, Vadivelu VM
    Bioresour Technol, 2014 Jun;161:441-5.
    PMID: 24725384 DOI: 10.1016/j.biortech.2014.03.104
    Aerobic dynamic feeding (ADF) strategy was applied in sequencing batch reactor (SBR) to accumulate polyhydroxyalkanoate (PHA) in aerobic granules. The aerobic granules were able to remove 90% of the COD from palm oil mill effluent (POME). The volatile fatty acids (VFAs) in the POME are the sole source of the PHA accumulation. In this work, 100% removal of propionic and butyric acids in the POME were observed. The highest amount of PHA produced in aerobic granules was 0.6833mgPHA/mgbiomass. The PHA formed was identified as a P (hydroxybutyrate-co-hydroxyvalerate) P (HB-co-HV).
    Matched MeSH terms: Fatty Acids, Volatile/chemistry
  3. Influence of roxithromycin as antibiotic residue on volatile fatty acids recovery in anaerobic fermentation of waste activated sludge
    Chen H, Zeng X, Zhou Y, Yang X, Lam SS, Wang D
    J Hazard Mater, 2020 07 15;394:122570.
    PMID: 32244145 DOI: 10.1016/j.jhazmat.2020.122570
    The removal of antibiotics and resistance genes in wastewater treatment plants has attracted widespread attention, but the potential role of residual antibiotics in the disposal of waste activated sludge (WAS) has not been clearly understood. In this study, the effect of roxithromycin (ROX) on volatile fatty acid (VFA) recovery from WAS anaerobic fermentation was investigated. The experimental results showed that ROX made a positive contribution to the production of VFAs. With the increase of ROX dosages from 0 to 100 mg/kg TSS, the maximum accumulation of VFAs increased from 295 to 610 mg COD/L. Mechanism studies revealed that ROX promoted the solubilization of WAS by facilitating the disruption of extracellular polymeric substances. In addition, ROX enhanced the activity of acetate kinase and inhibited the activities of α-glucosidase and coenzyme F420, and showed a stronger inhibitory effect on methane production than the hydrolysis process, thus resulting in an increase in VFA accumulation. These findings provide a new insight for the role of antibiotics in anaerobic fermentation of WAS.
    Matched MeSH terms: Fatty Acids, Volatile*
  4. Short-chain fatty acids: possible regulators of insulin secretion
    Rosli NSA, Abd Gani S, Khayat ME, Zaidan UH, Ismail A, Abdul Rahim MBH
    Mol Cell Biochem, 2023 Mar;478(3):517-530.
    PMID: 35943655 DOI: 10.1007/s11010-022-04528-8
    The benefits of gut microbiota-derived short-chain fatty acids (SCFAs) towards health and metabolism have been emerging since the past decade. Extensive studies have been carried out to understand the mechanisms responsible in initiating the functionalities of these SCFAs towards body tissues, which greatly involves the SCFA-specific receptors free fatty acid receptor 2 (FFAR2) and free fatty acid receptor 3 (FFAR3). This review intends to discuss the potential of SCFAs particularly in regulating insulin secretion in pancreatic β-cells, by explaining the production of SCFAs in the gut, the fate of each SCFAs after their production, involvement of FFAR2 and FFAR3 signalling mechanisms and their impacts on insulin secretion. Increased secretion of insulin after SCFAs treatments were reported in many studies, but contradicting evidence also exist in several other studies. Hence, no clear consensus was achieved in determining the true potential of SCFA in regulating insulin secretion. In this review, we explore how such differences were possible and hopefully be able to shed some perspectives in understanding SCFAs-signalling behaviour and preferences.
    Matched MeSH terms: Fatty Acids, Volatile/metabolism
  5. A comprehensive review on two-stage integrative schemes for the valorization of dark fermentative effluents
    Sivagurunathan P, Kuppam C, Mudhoo A, Saratale GD, Kadier A, Zhen G, et al.
    Crit Rev Biotechnol, 2018 Sep;38(6):868-882.
    PMID: 29264932 DOI: 10.1080/07388551.2017.1416578
    This review provides the alternative routes towards the valorization of dark H2 fermentation effluents that are mainly rich in volatile fatty acids such as acetate and butyrate. Various enhancement and alternative routes such as photo fermentation, anaerobic digestion, utilization of microbial electrochemical systems, and algal system towards the generation of bioenergy and electricity and also for efficient organic matter utilization are highlighted. What is more, various integration schemes and two-stage fermentation for the possible scale up are reviewed. Moreover, recent progress for enhanced performance towards waste stabilization and overall utilization of useful and higher COD present in the organic source into value-added products are extensively discussed.
    Matched MeSH terms: Fatty Acids, Volatile
  6. A gutsy performance: the potential for supplementation of short-chain fatty acids to benefit athletic health, exercise performance, and recovery
    Ong MLY, Green CG, Bongiovanni T, Heaney LM
    Benef Microbes, 2023 Dec 12;14(6):565-590.
    PMID: 38350483 DOI: 10.1163/18762891-20230069
    The gut microbiome is known to play an important role in the day-to-day physiology and health of the human host. It is, therefore, not surprising that there is interest surrounding the gut microbiome and its potential to benefit athletic health and performance. This has, in part, been driven by the consideration that gut bacterial by-products (i.e. metabolic waste) could be harnessed by the host and utilised for a beneficial outcome. The concept of harnessing bacterial metabolites as beneficial health modulators has developed the theory of leveraging short-chain fatty acids (SCFAs) as novel supplements for enhancing athletic performance. This review discusses the current literature investigating SCFA administration in cellular, animal, and human models, with the aim of linking the demonstrated physiological/biochemical mechanisms to potential exercise/athletic benefit. In addition, practical implications and factors relating to SCFA-supplementation in athletic populations are considered. The literature demonstrates a tangible rationale that SCFAs can have a positive impact on human physiology to afford benefits to the athletic population. These advantages include the capacity to improve respiratory immunity to combat elevated levels/severity of upper respiratory tract infections often reported in athletes; the blunting of pro-inflammatory and pro-fibrotic pathways to aid in exercise recovery; and the role of SCFAs as usable energy sources and metabolism modulators to fuel exercise and improve performance and/or endurance capacity. However, there is currently minimal research completed in human participants and thus further investigations into the direct benefit of SCFAs in exercise performance and/or recovery-based studies are required.
    Matched MeSH terms: Fatty Acids, Volatile
  7. VFA and ammonia from residential food waste as indicators of odor potential
    Qamaruz-Zaman N, Milke MW
    Waste Manag, 2012 Dec;32(12):2426-30.
    PMID: 22819598 DOI: 10.1016/j.wasman.2012.06.023
    Research was conducted to determine suitable chemical parameters as indicators of odor from decomposing food wastes. Prepared food scraps were stored in 18 l plastic buckets (2 kg wet weight each) at 20 °C and 8 °C to reproduce high and low temperature conditions. After 1, 3, 7, 10 and 14 days of storage, the odor from the buckets were marked to an intensity scale of 0 (no odor) to 5 (intense) and the corresponding leachate analyzed for volatile fatty acids, ammonia and total organic carbon. A linear relationship between odor intensity and the measured parameter indicates a suitable odor indicator. Odor intensified with longer storage period and warmer surroundings. The study found ammonia and isovaleric acid to be promising odor indicators. For this food waste mixture, offensive odors were emitted if the ammonia and isovaleric acid contents exceeded 360 mg/l and 940 mg/l, respectively.
    Matched MeSH terms: Fatty Acids, Volatile/chemistry*
  8. Fulltext Characterization and stability of short-chain fatty acids modified starch Pickering emulsions
    Abdul Hadi N, Marefati A, Matos M, Wiege B, Rayner M
    Carbohydr Polym, 2020 Jul 15;240:116264.
    PMID: 32475554 DOI: 10.1016/j.carbpol.2020.116264
    Acetylated, propionylated and butyrylated rice and quinoa starches at different levels of modification and starch concentrations, were used to stabilize oil-in-water starch Pickering emulsions at 10% oil fraction. Short-chain fatty acid modified starch Pickering emulsions (SPEs) were characterized after emulsification and after 50 days of storage. The particle size distribution, microstructure, emulsion index, and stability were evaluated. An increase in starch concentration led to a decrease of emulsion droplet sizes. Quinoa starch has shown the capability of stabilizing Pickering emulsions in both the native and modified forms. The emulsifying capacity of SPEs was improved by increasing the chain length of SCFA. Modified quinoa starch with higher chain lengths (i.e. propionylated and butyrylated), at higher levels of modification, showed higher emulsion index (>71%) and stability over the entire 50 days storage. At optimized formulation, SCFA-starch particles have the potential in stabilizing emulsions for functional foods, pharmaceutical formulations, or industrial food applications.
    Matched MeSH terms: Fatty Acids, Volatile/chemistry*
  9. Fulltext Microbiome and ischemic stroke: A systematic review
    Lee YT, Mohd Ismail NI, Wei LK
    PLoS One, 2021;16(1):e0245038.
    PMID: 33439913 DOI: 10.1371/journal.pone.0245038
    BACKGROUND: Ischemic stroke is one of the non-communicable diseases that contribute to the significant number of deaths worldwide. However, the relationship between microbiome and ischemic stroke remained unknown. Hence, the objective of this study was to perform systematic review on the relationship between human microbiome and ischemic stroke.

    METHODS: A systematic review on ischemic stroke was carried out for all articles obtained from databases until 22nd October 2020. Main findings were extracted from all the eligible studies.

    RESULTS: Eighteen eligible studies were included in the systematic review. These studies suggested that aging, inflammation, and different microbial compositions could contribute to ischemic stroke. Phyla Firmicutes and Bacteroidetes also appeared to manipulate post-stroke outcome. The important role of microbiota-derived short-chain fatty acids and trimethylamine N-oxide in ischemic stroke were also highlighted.

    CONCLUSIONS: This is the first systematic review that investigates the relationship between microbiome and ischemic stroke. Aging and inflammation contribute to differential microbial compositions and predispose individuals to ischemic stroke.

    Matched MeSH terms: Fatty Acids, Volatile/metabolism*
  10. The Athlete and Gut Microbiome: Short-chain Fatty Acids as Potential Ergogenic Aids for Exercise and Training
    Bongiovanni T, Yin MOL, Heaney L
    Int J Sports Med, 2021 Dec;42(13):1143-1158.
    PMID: 34256388 DOI: 10.1055/a-1524-2095
    Short-chain fatty acids (SCFAs) are metabolites produced in the gut via microbial fermentation of dietary fibers referred to as microbiota-accessible carbohydrates (MACs). Acetate, propionate, and butyrate have been observed to regulate host dietary nutrient metabolism, energy balance, and local and systemic immune functions. In vitro and in vivo experiments have shown links between the presence of bacteria-derived SCFAs and host health through the blunting of inflammatory processes, as well as purported protection from the development of illness associated with respiratory infections. This bank of evidence suggests that SCFAs could be beneficial to enhance the athlete's immunity, as well as act to improve exercise recovery via anti-inflammatory activity and to provide additional energy substrates for exercise performance. However, the mechanistic basis and applied evidence for these relationships in humans have yet to be fully established. In this narrative review, we explore the existing knowledge of SCFA synthesis and the functional importance of the gut microbiome composition to induce SCFA production. Further, changes in gut microbiota associated with exercise and various dietary MACs are described. Finally, we provide suggestions for future research and practical applications, including how these metabolites could be manipulated through dietary fiber intake to optimize immunity and energy metabolism.
    Matched MeSH terms: Fatty Acids, Volatile/administration & dosage*
  11. The influence of moisture content on the production of odor from food waste using path analysis
    Qamaruz-Zaman N, Abdul-Sukor NS, Ab-Rahman SA, Yaacof N
    Environ Sci Pollut Res Int, 2019 May;26(13):13658-13663.
    PMID: 30955198 DOI: 10.1007/s11356-019-04808-9
    Path analysis has been largely used in marketing research but has recently been applied in an environmental management context. This study evaluated the potential of path analysis in identifying the influence of moisture content on odor from decomposing food waste. Food waste with varying moisture content was monitored for odor concentration, microbial population density, oxygen uptake rate, volatile fatty acids, ammonia, and hydrogen sulfide. These various parameters were later analyzed using SmartPLS 3.0 software to produce the path analysis model using simultaneous equation modeling. Results indicate that odor concentration of food waste was not directly affected by moisture content (not significant, t-statistical 1.46  1.96) and subsequently odor. In order to manage food waste-related odors, it is recommended that the waste be kept at a moisture content lower than 40%. This is especially critical if prolonged storage is unavoidable.
    Matched MeSH terms: Fatty Acids, Volatile/chemistry*
  12. Enzymatically synthesised fructooligosaccharides from sugarcane syrup modulate the composition and short-chain fatty acid production of the human intestinal microbiota
    Hajar-Azhari S, Hafiz Abd Rahim M, Razid Sarbini S, Muhialdin BJ, Olusegun L, Saari N
    Food Res Int, 2021 11;149:110677.
    PMID: 34600679 DOI: 10.1016/j.foodres.2021.110677
    Fructooligosaccharides can be produced by direct enzymatic conversion from sucrose-rich sugarcane syrup (SS) consisting of 58.93% sucrose yielding 21.28 g FOS/100 g sucrose. This study evaluated the prebiotic effect of unpurified/purified SS containing FOS for the modulation of the human intestinal microbial composition and short-chain fatty acid production. The unpurified and purified FOS substrates, which were a mixture of 1-kestose, nystose and 1F-fructosylnystose, were supplemented into human faecal culture using a pH-controlled batch fermentation system and significantly increased the Bifidobacterium counts after 5 h fermentation, while Bacteroides/Prevotella counts were highest throughout 24 h fermentation. Meanwhile, Lactobacillus/Enterococcus exhibited a slight increase after 5 h fermentation before reaching a plateau afterwards. The steady Bacteroides/Prevotella growth and increased Bifidobacterium population promoted an increase in the production of short-chain fatty acids acetate (58 ± 2.70 mM), propionate (9.19 ± 5.94 mM) and butyrate (7.15 ± 2.28 mM). These results provide evidence that representative gut microbiota could utilise the enzymatically synthesised FOS to generate short-chain fatty acids as metabolites in pH-controlled conditions, thus FOS from SS are a potential prebiotic ingredient for foods and health drinks.
    Matched MeSH terms: Fatty Acids, Volatile
  13. Preliminary observation on the effect of baking soda volume on controlling odour from discarded organic waste
    Qamaruz-Zaman N, Kun Y, Rosli RN
    Waste Manag, 2015 Jan;35:187-90.
    PMID: 25445259 DOI: 10.1016/j.wasman.2014.09.017
    Food wastes with high moisture and organic matter content are likely to emit odours as a result of the decomposition process. The management of odour from decomposing wastes is needed to sustain the interest of residents and local councils in the source separation of kitchen wastes. This study investigated the potential of baking soda (at 50 g, 75 g and 100g per kg food waste) to control odour from seven days stored food waste. It was found that 50 g of baking soda, spread at the bottom of 8l food wastes bin, can reduce the odour by about 70%. A higher amount (above 100g) is not advised as a pH higher than 9.0 may be induced leading to the volatilization of odorous ammonia. This research finding is expected to benefit the waste management sector, food processing industries as well as the local authorities where malodour from waste storage is a pressing issue.
    Matched MeSH terms: Fatty Acids, Volatile/analysis; Fatty Acids, Volatile/chemistry
  14. Comparing the effects of different dietary organic acids on the growth, intestinal short-chain fatty acids, and liver histopathology of red hybrid tilapia (Oreochromis sp.) and potential use of these as preservatives
    Ebrahimi M, Daeman NH, Chong CM, Karami A, Kumar V, Hoseinifar SH, et al.
    Fish Physiol Biochem, 2017 Aug;43(4):1195-1207.
    PMID: 28349418 DOI: 10.1007/s10695-017-0365-0
    Dietary organic acids are increasingly being investigated as a potential means of improving growth and nutrient utilization in aquatic animals. A 9-week study was performed to compare equal amounts (2%) of different organic acids (sodium butyrate, acetate, propionate, or formate) on the growth, muscle proximate composition, fatty acid composition, cholesterol and lipid peroxidation, differential cell counts, plasma biochemistry, intestinal short-chain fatty acid (SCFA) level, and liver histopathology to red hybrid tilapia (Oreochromis sp.) (initial mean weight of 2.87 g). A second experiment was performed to determine their effects on lipid peroxidation and trimethylamine (TMA) when added at 1% to tilapia meat and left out for 24 h. The results of the first experiment showed no treatment effect to growth, feeding efficiencies, or muscle fatty acid composition, but all dietary organic acids significantly decreased intestinal SCFA. Dietary butyrate and propionate significantly decreased muscle lipid peroxidation compared to the control group, but the dietary formate treatment had the lowest lipid peroxidation compared to all treatments. Muscle crude protein and lipid in tilapia fed the formate diet were significantly lower and higher, respectively, and showed evidence of stress based on the differential cell counts, significantly higher plasma glucose and liver glycogen, as well as inflammatory responses in the liver. Although a potential benefit of dietary organic acids was a reduction to lipid peroxidation, this could be accomplished post-harvest by direct additions to the meat. In addition, inclusions of butyrate and propionate to tilapia meat significantly decreased TMA, which might be a more cost-effective option to improve the shelf life of tilapia products.
    Matched MeSH terms: Fatty Acids, Volatile/adverse effects; Fatty Acids, Volatile/pharmacology*
  15. The potential of resistant starch as a prebiotic
    Zaman SA, Sarbini SR
    Crit Rev Biotechnol, 2016 Jun;36(3):578-84.
    PMID: 25582732 DOI: 10.3109/07388551.2014.993590
    Resistant starch is defined as the total amount of starch and the products of starch degradation that resists digestion in the small intestine. Starches that were able to resist the digestion will arrive at the colon where they will be fermented by the gut microbiota, producing a variety of products which include short chain fatty acids that can provide a range of physiological benefits. There are several factors that could affect the resistant starch content of a carbohydrate which includes the starch granule morphology, the amylose-amylopectin ratio and its association with other food component. One of the current interests on resistant starch is their potential to be used as a prebiotic, which is a non-digestible food ingredient that benefits the host by stimulating the growth or activity of one or a limited number of beneficial bacteria in the colon. A resistant starch must fulfill three criterions to be classified as a prebiotic; resistance to the upper gastrointestinal environment, fermentation by the intestinal microbiota and selective stimulation of the growth and/or activity of the beneficial bacteria. The market of prebiotic is expected to reach USD 198 million in 2014 led by the export of oligosaccharides. Realizing this, novel carbohydrates such as resistant starch from various starch sources can contribute to the advancement of the prebiotic industry.
    Matched MeSH terms: Fatty Acids, Volatile
  16. Diet-related gut microbial metabolites and sensing in hypertension
    R Muralitharan R, Marques FZ
    J Hum Hypertens, 2021 02;35(2):162-169.
    PMID: 32733062 DOI: 10.1038/s41371-020-0388-3
    Advances in sequencing technology have increased our understanding of the composition of the gut microbiota and their contribution to health and disease states, including in cardiovascular diseases such as hypertension. The gut microbiota is heavily influenced by diet and produce metabolites such as short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO) from various food sources. SCFAs, such as acetate, propionate, and butyrate, have been shown to have blood pressure, cardiac hypertrophy, and fibrosis lowering properties, while TMAO has been associated with increased risk of major cardiovascular adverse events and mortality. Some of these metabolites have known ligands (for example, SCFA receptors such as GPR41, GPR43, GPR109a, and Olf78 in mice/OR51E2 in humans) which could potentially be manipulated as therapeutic targets for hypertension. In this review, we discuss several types of diet-related gut microbial metabolites and their sensing mechanisms that are relevant for hypertension, and the future directions for the field.
    Matched MeSH terms: Fatty Acids, Volatile
  17. Fulltext Performance and operational characteristics of modified anaerobic hybrid baffled (MAHB) reactor treating low strength recycled paper mill effluent (RPME) wastewater
    Siti Roshayu Hassan, Nastaein Qamaruz Zaman, Irvan Dahlan
    Scientific Research Journal, 2014;11(2):0-0.
    MyJurnal
    The performance and operational characteristics of a laboratory scale modified anaerobic hybrid baffled (MAHB) reactor were studied using recycled paper mill effluent (RPME) wastewater. MAHB reactor was continuously operated at 35°C for 90 days with organic loading rate (OLR) increased from 0.14 to 0.57 g/L/dy. This present study demonstrated that the system was proficient in treating low strength RPME wastewater. Highest carbon oxygen demand (COD) removal were recorded up to 97% for an organic loading of 0.57 g /L/dy while effluent alkalinity assured that the system pH in the MAHB compartments were of great advantages to acidogens and methanogens respectively. Methane and biogas production rate shows increment as the load increases, which evidently indicated that the most significant approach to enhance gas production rates involves the increment of incoming substrate moderately. Variations of biogas and volatile fatty acid (VFA) in different compartments of MAHB reactor indicated the chronological degradation of substrate. The compartmental structure of MAHB reactor provided its strong ability to resist shock loads. From this present study, it shows the potential usage of MAHB reactor broadens the usage of multi-phase anaerobic technology for industrial wastewater treatment.
    Matched MeSH terms: Fatty Acids, Volatile
  18. 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: Fatty Acids, Volatile
  19. The effect of the labile organic fraction in food waste and the substrate/inoculum ratio on anaerobic digestion for a reliable methane yield
    Kawai M, Nagao N, Tajima N, Niwa C, Matsuyama T, Toda T
    Bioresour Technol, 2014 Apr;157:174-80.
    PMID: 24556370 DOI: 10.1016/j.biortech.2014.01.018
    Influence of the labile organic fraction (LOF) on anaerobic digestion of food waste was investigated in different S/I ratio of 0.33, 0.5, 1.0, 2.0 and 4.0g-VSsubstrate/g-VSinoculum. Two types of substrate, standard food waste (Substrate 1) and standard food waste with the supernatant (containing LOF) removed (Substrate 2) were used. Highest methane yield of 435ml-CH4g-VS(-1) in Substrate 1 was observed in the lowest S/I ratio, while the methane yield of the other S/I ratios were 38-73% lower than the highest yield due to acidification. The methane yields in Substrate 2 were relatively stable in all S/I conditions, although the maximum methane yield was low compared with Substrate 1. These results showed that LOF in food waste causes acidification, but also contributes to high methane yields, suggesting that low S/I ratio (<0.33) is required to obtain a reliable methane yield from food waste compared to other organic substrates.
    Matched MeSH terms: Fatty Acids, Volatile/metabolism
  20. Fulltext Improved properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) produced by Comamonas sp. EB172 utilizing volatile fatty acids by regulating the nitrogen source
    Zakaria MR, Ariffin H, Abd-Aziz S, Hassan MA, Shirai Y
    Biomed Res Int, 2013;2013:237806.
    PMID: 24106698 DOI: 10.1155/2013/237806
    This study presents the effect of carbon to nitrogen ratio (C/N) (mol/mol) on the cell growth and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) accumulation by Comamonas sp. EB172 in 2 L fermenters using volatile fatty acids (VFA) as the carbon source. This VFA was supplemented with ammonium sulphate and yeast extract in the feeding solution to achieve C/N (mol/mol) 5, 15, 25, and 34.4, respectively. By extrapolating the C/N and the source of nitrogen, the properties of the polymers can be regulated. The number average molecular weight (M n ) of P(3HB-co-3HV) copolymer reached the highest at 838 × 10(3) Da with polydispersity index (PDI) value of 1.8, when the culture broth was supplemented with yeast extract (C/N 34.4). Tensile strength and Young's modulus of the copolymer containing 6-8 mol% 3HV were in the ranges of 13-14.4 MPa and 0.26-0.34 GPa, respectively, comparable to those of polyethylene (PE). Thus, Comamonas sp. EB172 has shown promising bacterial isolates producing polyhydroxyalkanoates from renewable carbon materials.
    Matched MeSH terms: Fatty Acids, Volatile/chemistry*
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