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Journal ArticleDOI

Interactive metabolic regulations during biomethanation ofLeucaena leucocephala

01 Oct 1990-Applied Biochemistry and Biotechnology (Springer Science and Business Media LLC)-Vol. 26, Iss: 1, pp 73-84
TL;DR: The controlled rate of cellulose hydrolysis, levels of volatile acids, and steady-state levels of soluble carbohydrates and reducing sugars observed during active methanogenesis are indicative of interactive metabolic regulations.
Abstract: Biomethanation of leaves of the legumeL. leucocephala operated in batch reactors at different input volatile solids (12–18 g/L) proceeded in distinct metabolic phases. An initial cellulolytic phase of 4 d was followed by an early and active methanogenic phases (5–21 d) and a terminal phase of low-rate methanogenesis. Hydrolysis of cellulose was concentration-dependent and resulted in increased volatile acid levels. The trend of changes showed some variations at different input volatile solids. The changes in the levels of volatile acids followed an oscillatory pattern. The controlled rate of cellulose hydrolysis, levels of volatile acids, and steady-state levels of soluble carbohydrates and reducing sugars observed during active methanogenesis are indicative of interactive metabolic regulations.
Topics: Cellulose (56%), Hydrolysis (53%), Methanogenesis (53%)
Citations
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Journal ArticleDOI
TL;DR: Heat, moisture, chemical treatments, ensiling, rotation feeding, cutting management of the plant, new hybrids, introducing micro-organisms into the rumen of ruminants that are unable to detoxify mimosine, and preparing protein isolate from Leucaena seeds have all been used to overcome Mimosine toxicity.
Abstract: Leucaena leucocephala is one of the fastest-growing leguminous trees. Its foliage is used as animal feed, and its leaves and seeds are used as human food in Central America, Indonesia, and Thailand...

33 citations


Cites background from "Interactive metabolic regulations d..."

  • ...It is an important crop encouraged under the social forestry schemes in drought-prone areas and semi-arid tracts in India, as it provides useful timber as well as leaves for fuel and energy and feed purposes [1, 3-6]....

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Journal ArticleDOI
TL;DR: The concept of interactive metabolic control earlier proposed has been validated based on the levels of various metabolites detected and the overall decrease in volatile solid level was 65%, whereas the collagen level declined by 85%.
Abstract: Anaerobic digestion of calf skin collagenous waste was optimized for a batch process based on accelerated maximal methane yield per gram of input volatile solid. A kinetic analysis with respect to changes in the levels of volatile solid, collagen, amino sugars, amino acids, hydroxyproline, ammonium ions, and volatile fatty acid were followed for a period of 80 d. Distinct metabolic phases included an initial high rate collagenolysis for 4d, with 50% degradation and was followed by an acidogenic phase between 4-12 d with volatile fatty acids levels increasing to 215 mmol/L. Subsequently methanogenesis ensued and was maximal between 12-24 d when volatile fatty acids attained steady state levels. During the period of 80 d, the overall decrease in volatile solid level was 65%, whereas the collagen level declined by 85% with 0.45 L of methane yield/g of volatile solid degraded. Based on the levels of various metabolites detected, the concept of interactive metabolic control earlier proposed has been validated.

26 citations


Journal ArticleDOI
TL;DR: The results suggest that utilization of methanol by the mixed culture would involve metabolic interactions between the Pseudomonas sp.
Abstract: An anaerobic methylotrophic methanogenic enrichment culture, with sustained metabolic characteristics, including that of methanation for over a decade, was the choice of the present study on interspecies interactions. Growth and methanation by the enrichment were suppressed in the presence of antibiotics, and no methanogen grown on methanol could be isolated using stringent techniques. The present study confirmed syntrophic metabolic interactions in this enrichment with the isolation of a strain ofPseudomonas sp. The organism had characteristic metabolic versatility in metabolizing a variety of substrates including alcohols, aliphatic acids, amino acids, and sugars. Anaerobic growth was favoured with nitrate in the growth medium. Cells grown anaerobically with methanol, revealed maximal nitrate reductase activity. Constitutive oxidative activity of the membrane system emerged from the high-specific oxygen uptake and nitrate reductase activities of the aerobically and anerobically grown cells respectively. Cells grown anaerobically on various alcohols effectively oxidized methanol in the presence of flavins, cofactor FAD and the methanogenic cofactor F420, suggesting a constitutive alcohol oxidizing capacity. In cells grown anaerobically on methanol, the rate of methanol oxidation with F420 was three times that of FAD. Efficient utilization of alcohols in the presence of F420 is a novel feature of the present study. The results suggest that utilization of methanol by the mixed culture would involve metabolic interactions between thePseudomonas sp. and the methanogen(s). Methylotrophic, methanogenic partnership involving an aerobe is a novel feature hitherto unreported among anaerobic syntrophic associations and is of ecological significance.

8 citations


Cites background from "Interactive metabolic regulations d..."

  • ...In addition, research from our laboratory provided evidence for an efficient interactive metabolic control prevailing during active biomethanation of polymeric carbohydrates (Krishnan and Lalitha 1990) or proteins (Swaminathan 1995)....

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  • ...Involvement of microbial consortia or communities composed of two or more taxa to effect efficient catabolism of different compounds were shown by many studies including those from our laboratory (Krishnan and Lalitha 1990; Lalitha et al 1994a; Wolfaardt et al 1994)....

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Journal ArticleDOI
TL;DR: Enrichment of methanogenic cultures on methanol from the microbial population in the anaerobic digesters operated on agricultural wastes revealed a high rate of biomethanation efficiency and signify metabolic partnerships in the methylotrophic biochemical mechanisms operative toward energy recovery.
Abstract: Enrichment of methanogenic cultures on methanol from the microbial population in the anaerobic digesters operated on agricultural wastes revealed a high rate of biomethanation efficiency. Routine maintenance of this enrichment in a minimal basal medium at room temperature resulted in maximal growth in 40–50 d, and indicated pigment production toward the end of the growth phase. The cultures grown in three different media, with different substrates under light and dark conditions, were analyzed for protein, pigment, and gaseous products, and morphological studies were carried out by light, phase-contrast, fluorescence, and electron microscopy. In different media with methanol as substrate, growth and pigment production were maximal for the light-grown cells, decreasing in the order: phototrophic (PS(m)) > mineral > basal medium. Methanation and phototrophic growth were inversely correlated under lightgrown conditions. In contrast, growth in the dark was predominently methanogenic in the decreasing order: mineral > basal > PS (m). Among other growth conditions tested, utilization of phototrophic substrates under light and dark conditions indicated the following: 1. Basal and mineral media were supportive of methanogenic growth under both light and dark conditions, although methane yields under light-grown conditions were low; 2. Among the different substrates tested, methanol-grown cells gave the highest methane yield in the dark and; 3. Phototrophic growth in PS medium with succinate, malate, and pyruvate was better than that with methanol.

5 citations


References
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Book
01 Jan 1992-
Abstract: Set your standards with these standard methods. This is it: the most widely read publication in the water industry, your all-inclusive reference tool. This comprehensive reference covers all aspects of USEPA-approved water analysis methods. More than 400 methods - all detailed step-by-step; 8 vibrant, full-color pages of aquatic algae illustrations; Never-before-seen figures that will help users with toxicity testing and the identification of apparatus used in the methods; Over 300 superbly illustrated figures; A new analytical tool for a number of inorganic nonmetals; Improved coverage of data evaluation, sample preservation, and reagant water; And much more!

78,276 citations


Journal ArticleDOI
Abstract: Simple sugars, oligosaccharides, polysaccharides, and their derivatives, including the methyl ethers with free or potentially free reducing groups, give an orangeyellow color w-hen treated with phenol and concentrated sulfuric acid. The reaction is sensitive and the color is stable. By use of this phenol-sulfuric acid reaction, a method has been developed to determine submicro amounts of sugars and related substances. In conjunction with paper partition chromatography the method is useful for the determination of the composition of polysaccharides and their methyl derivatives.

41,792 citations



Journal ArticleDOI
TL;DR: This article corrects the article on p. 517 in vol.
Abstract: [This corrects the article on p. 517 in vol. 41.].

511 citations


Journal ArticleDOI
TL;DR: A chronology of key events and events in the history of the United States, as well as some of the key stories and anecdotes, are presented.
Abstract: Historical ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . Outlook . . . . . .. ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . ...... . . . . . . . . . . . . . . . . SUBSTRATE-PRODUCT RELATIONSHIPS. .. ..

392 citations