scholarly journals Impact of Alkaline Pretreatment to Enhance Volatile Fatty Acids (VFAs) Production from Rice Husk

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Qian Fang ◽  
Sinmin Ji ◽  
Dingwu Huang ◽  
Zhouyue Huang ◽  
Zilong Huang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Rice Husk ◽  
Volatile Fatty Acids ◽  
Alkaline Pretreatment ◽  
Rice Husks ◽  
Acid Fermentation ◽  
Study Results

This study explores the use of alkaline pretreatments to improve the hydrolyzation of rice husks to produce volatile fatty acids (VFAs). The study investigated the effects of reagent concentration and pretreatment time on protein, carbohydrates, and dissolved chemical oxygen demand (SCOD) dissolution after the pretreatment. The optimum alkaline pretreatment conditions were 0.30 g NaOH (g VS)−1, with a reaction time of 48 h. The experimental results show that when comparing the total VFA (TVFA) yields from the alkaline-pretreated risk husk with those from the untreated rice husk, over 14 d and 2 d, the maximum value reached 1237.7 and 716.0 mg·L−1 with acetic acid and propionic acid and with acetic acid and butyric acid, respectively. After the alkaline pretreatment, TVFAs increased by 72.9%; VFA accumulation grew over time. The study found that alkaline pretreatment can improve VFA yields from rice husks and transform butyric acid fermentation into propionic acid fermentation. The study results can provide guidelines to support the comprehensive utilization of rice husk and waste treatment.

scholarly journals Enhanced lipid production by Yarrowia lipolytica cultured with synthetic and waste-derived high-content volatile fatty acids under alkaline conditions

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ruiling Gao ◽  
Zifu Li ◽  
Xiaoqin Zhou ◽  
Wenjun Bao ◽  
Shikun Cheng ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Yarrowia Lipolytica ◽  
Butyric Acid ◽  
Lipid Content ◽  
Volatile Fatty Acids ◽  
Lipid Production ◽  
Initial Ph ◽  
Alkaline Conditions

Abstract Background Volatile fatty acids (VFAs) can be effective and promising alternate carbon sources for microbial lipid production by a few oleaginous yeasts. However, the severe inhibitory effect of high-content (> 10 g/L) VFAs on these yeasts has impeded the production of high lipid yields and their large-scale application. Slightly acidic conditions have been commonly adopted because they have been considered favorable to oleaginous yeast cultivation. However, the acidic pH environment further aggravates this inhibition because VFAs appear largely in an undissociated form under this condition. Alkaline conditions likely alleviate the severe inhibition of high-content VFAs by significantly increasing the dissociation degree of VFAs. This hypothesis should be verified through a systematic research. Results The combined effects of high acetic acid concentrations and alkaline conditions on VFA utilization, cell growth, and lipid accumulation of Yarrowia lipolytica were systematically investigated through batch cultures of Y. lipolytica by using high concentrations (30–110 g/L) of acetic acid as a carbon source at an initial pH ranging from 6 to 10. An initial pH of 8 was determined as optimal. The highest biomass and lipid production (37.14 and 10.11 g/L) were obtained with 70 g/L acetic acid, whereas cultures with > 70 g/L acetic acid had decreased biomass and lipid yield due to excessive anion accumulation. Feasibilities on high-content propionic acid, butyric acid, and mixed VFAs were compared and evaluated. Results indicated that YX/S and YL/S of cultures on butyric acid (0.570, 0.144) were comparable with those on acetic acid (0.578, 0.160) under alkaline conditions. The performance on propionic acid was much inferior to that on other acids. Mixed VFAs were more beneficial to fast adaptation and lipid production than single types of VFA. Furthermore, cultures on food waste (FW) and fruit and vegetable waste (FVW) fermentate were carried out and lipid production was effectively improved under this alkaline condition. The highest biomass and lipid production on FW fermentate reached 14.65 g/L (YX/S: 0.414) and 3.20 g/L (YL/S: 0.091) with a lipid content of 21.86%, respectively. By comparison, the highest biomass and lipid production on FVW fermentate were 11.84 g/L (YX/S: 0.534) and 3.08 g/L (YL/S: 0.139), respectively, with a lipid content of 26.02%. Conclusions This study assumed and verified that alkaline conditions (optimal pH 8) could effectively alleviate the lethal effect of high-content VFA on Y. lipolytica and significantly improve biomass and lipid production. These results could provide a new cultivation strategy to achieve simple utilizations of high-content VFAs and increase lipid production. Feasibilities on FW and FVW-derived VFAs were evaluated, and meaningful information was provided for practical applications.

Toxicity of pH, Ammonia and Volatile Fatty Acids on Hydrogenotrophic Methanogen-Enriched Sludge

2014 ◽  
Vol 955-959 ◽  
pp. 527-531
Author(s):  
Jian Zheng Li ◽  
Yu Peng Zhang ◽  
Chong Liu ◽  
Ze Yu Tang
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Anaerobic Digestion ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Volatile Fatty Acids ◽  
Batch Experiments ◽  
Inhibitory Effects ◽  
Hydrogenotrophic Methanogen ◽  
The Impact

The activities of methanogen are easily affected by inhibitory substances and lead to anaerobic digestion failure. To investigate inhibitory effects on methanogenesis of a methanogen-enriched sludge, pH, volatile fatty acids (such as acetic acid, propionic acid and butyric acid), and ammonia were used as inhibitory factors and a L16(45) orthogonal table was employed to design batch experiments. The result of variance analyses shows that pH has the greatest impact on the methanogenesis of the enriched culture. The impact of butyrate, NH3, acetate and propionate was decreased in order. DGGE finger-print shows that there was only one methanogen in the inoculum sludge.

Fermentation in the Rumen of the Sheep

1952 ◽  
Vol 29 (1) ◽  
pp. 57-65 ◽  
Author(s):  
F. V. GRAY ◽  
A. F. PILGRIM ◽  
H. J. RODDA ◽  
R. A. WELLER
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Active Carbon ◽  
Volatile Fatty Acids ◽  
Caproic Acid ◽  
Valeric Acid ◽  
Carboxyl Group

1. The mixture of volatile fatty acids in the rumen of the sheep has been shown to include formic acid, acetic acid, propionic acid, n-butyric acid, iso-butyric acid, n-valeric acid, another valeric acid isomer, caproic acid and an acid which is probably heptoic acid. The proportions in which they are present have been determined. 2. When acetic acid labelled with 14C in the carboxyl group was incorporated in the rumen fermentation in vitro, active carbon appeared later in all the higher acids. When labelled propionic acid was included in the fermentation, active carbon appeared in the valeric but not in the butyric acid. The results suggest a synthesis of the higher acids by condensation of the lower ones with 2-C compound in equilibrium with acetic acid. The extent of such syntheses and other possible modes of origin of the fatty acids are discussed.

scholarly journals Interconversions and production of volatile fatty acids in the sheep rumen

1965 ◽  
Vol 97 (1) ◽  
pp. 53-58 ◽  
Author(s):  
EN Bergman ◽  
RS Reid ◽  
MG Murray ◽  
JM Brockway ◽  
FG Whitelaw
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Steady State ◽  
Energy Expenditure ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Volatile Fatty Acids ◽  
Net Production ◽  
Constant Rate ◽  
Sheep Rumen

1. Sheep fed at a constant rate were infused intraruminally with [1-(14)C]-acetate, -propionate or -butyrate during 5hr. periods. 2. Volatile fatty acids were estimated in the rumen contents and steady-state conditions were obtained. 3. Of the butyric acid carbon 60% was in equilibrium with 20% of the acetic acid carbon, and 2-3g.atoms of carbon were interconverted/day. 4. Little interconversion took place between propionic acid, acetic acid or butyric acid. 5. The net production rates for acetic acid, propionic acid and butyric acid were 3.7, 1.0 and 0.7moles/day respectively. 6. The production of volatile fatty acids accounted for 80% of the animal's energy expenditure.

scholarly journals Pilot Study of the Effects of Polyphenols from Chestnut Involucre on Methane Production, Volatile Fatty Acids, and Ammonia Concentration during In Vitro Rumen Fermentation

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 108
Author(s):  
Yichong Wang ◽  
Sijiong Yu ◽  
Yang Li ◽  
Shuang Zhang ◽  
Xiaolong Qi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Acid Content ◽  
Volatile Fatty Acids ◽  
Rumen Fermentation ◽  
Gas Production ◽  
Quadratic Response ◽  
In Vitro Rumen Fermentation

Nutritional strategies can be employed to mitigate greenhouse emissions from ruminants. This article investigates the effects of polyphenols extracted from the involucres of Castanea mollissima Blume (PICB) on in vitro rumen fermentation. Three healthy Angus bulls (350 ± 50 kg), with permanent rumen fistula, were used as the donors of rumen fluids. A basic diet was supplemented with five doses of PICB (0%–0.5% dry matter (DM)), replicated thrice for each dose. Volatile fatty acids (VFAs), ammonia nitrogen concentration (NH3-N), and methane (CH4) yield were measured after 24 h of in vitro fermentation, and gas production was monitored for 96 h. The trial was carried out over three runs. The results showed that the addition of PICB significantly reduced NH3-N (p < 0.05) compared to control. The 0.1%–0.4% PICB significantly decreased acetic acid content (p < 0.05). Addition of 0.2% and 0.3% PICB significantly increased the propionic acid content (p < 0.05) and reduced the acetic acid/propionic acid ratio, CH4 content, and yield (p < 0.05). A highly significant quadratic response was shown, with increasing PICB levels for all the parameters abovementioned (p < 0.01). The increases in PICB concentration resulted in a highly significant linear and quadratic response by 96-h dynamic fermentation parameters (p < 0.01). Our results indicate that 0.2% PICB had the best effect on in-vitro rumen fermentation efficiency and reduced greenhouse gas production.

Studies on the production of volatile fatty acids from grass by rumen liquor in an artificial rumen: II. The volatile fatty acid production from dried grass

1957 ◽  
Vol 49 (2) ◽  
pp. 171-179 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Propionic Acid ◽  
Metabolic Pathways ◽  
Volatile Fatty Acid ◽  
Volatile Fatty Acids ◽  
Water Soluble ◽  
Fatty Acid Production ◽  
Growing Seasons ◽  
Titration Curves

1. A study has been made of the production of volatile fatty acids obtainable from dried grass and its gross water-soluble and water-insoluble separates, in the artificial rumen, over two growing seasons.2. In contradistinction to fresh grass, the dried grass gives a consistent production of acetic acid proportionately greater than propionic acid, at all stages of maturity, but when aqueous extracts of the dried grass, and the resultant extracted grass, respectively, are examined separately in the artificial rumen, it is found that the former yield preponderating amounts of acetic acid while the latter give amounts of propionic acid equal to, or exceeding, the corresponding productions of acetic acid.3. An examination of the titration curves for the total acids obtained from the dried grass, extracted grass and grass extract runs, indicates an approach to an incomplete relationship between the residual carbohydrate in the extracted grass and cellulose, while the grass extract reveals itself as the chief source of acetic acid in the whole dried grass, the acid being formed very speedily at the start of the run.4. The suggested sources and some of the possible metabolic pathways involved in the formation of v.f.a. from grass are discussed in the text.

scholarly journals Recovery of volatile fatty acids (VFA) from complex waste effluents using membranes

2013 ◽  
Vol 69 (3) ◽  
pp. 495-503 ◽  
Author(s):  
M.-P. Zacharof ◽  
R. W. Lovitt
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Butyric Acid ◽  
Volatile Fatty Acids ◽  
Agricultural Waste ◽  
Permeate Flux ◽  
Anaerobic Digesters ◽  
Waste Effluents

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes, including microfiltration and nanofiltration (NF), to concentrate volatile fatty acids (VFA). Microfiltration was applied successfully to produce sterile, particle-free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These were further treated using a variety of NF membranes: NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA) and LF10 (Nitto Denko, Japan), achieving retention ratios of up to 75%, and giving retentates of up to 53.94 mM of acetate and 28.38 mM of butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions, the highest productivity, retention and flux were achieved at pH 7. At higher pH there was a significant reduction in flux.

Effect of diet on individual volatile fatty acids in the rumen of sheep, with particular reference to the effect of low rumen pH and adaptation on high-starch diets

1957 ◽  
Vol 8 (6) ◽  
pp. 691 ◽  
Author(s):  
RL Reid ◽  
JP Hogan ◽  
PK Briggs
Keyword(s):  
Fatty Acids ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Acid Production ◽  
Volatile Fatty Acids ◽  
Maximum Level ◽  
Fatty Acid Production ◽  
Rumen Ph ◽  
Term Change ◽  
Effects Of Ph

Detailed data are presented on changes in the proportions of acetic, propionic, and butyric acids in the rumen after feeding on various diets. Pre-feeding proportions were constant on each diet but varied from a mixture of 72-76 per cent. acetic, 14-16 per cent. propionic, and 10-12 per cent. butyric acid on all-roughage diets to one of 63-65 per cent. acetic, 18-20 per cent. propionic, and 16-18 per cent. butyric acid on a diet containing 70 per cent. wheat grain. On all diets the proportion of propionic acid increased after feeding and reached a peak which coincided with the maximum level of total volatile fatty acids. The response of butyric acid was variable, low levels being recorded on a diet of lucerne chaff and on one containing a high proportion of cracked maize. The proportion of acetic acid always declined after feeding. These responses were modified in experiments on rations containing high proportions of wheaten starch, in which rumen pH fell below 5.0 as a result of lactic acid accumulation. When animals were first fed on such diets, a decline in rumen pH below 5.0-5.5 after feeding was always associated with a pronounced decline in the proportions of propionic and butyric acids, to levels as low as 8 and 5 per cent. respectively. Continued feeding of such diets did not affect the response of butyric acid, but there was evidence of a change in propionic acid production in response to low pH conditions, both in respect to short-term change during experiments in which low rumen pH levels were maintained for considerable periods and to long-term change when such diets were fed intermittently over considerable periods. The implications of these findings are discussed with respect to the effects of pH on individual volatile fatty acid production in the rumen, and on the qualitative nature of the microbial population and on their metabolic patterns.

Identification of the volatile fatty acid in the peripheral blood and rumen of cattle and the blood of other species

1951 ◽  
Vol 2 (1) ◽  
pp. 92 ◽  
Author(s):  
GL McClymont
Keyword(s):  
Acetic Acid ◽  
Fatty Acid ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Peripheral Blood ◽  
Molecular Basis ◽  
Volatile Fatty Acid ◽  
Volatile Fatty Acids ◽  
Bovine Blood ◽  
Mean Values

Volatile fatty acid isolated from nine samples of peripheral blood from four cows contained, on a molecular basis, from 90.0 to 97.0 per cent. of acetic acid (mean 93.3 per cent.). The remainder comprised, as mean values, propionic acid, 2.39 per cent.; butyric acid, 2.61 per cent.; and a group of at least three acids between butyric and octanoic, 1.84 per cent. The significance of the high proportion of acetic acid in the volatile fatty acid of bovine peripheral blood is discussed. Only traces of esterified acids lower than octanoic could be found in bovine blood lipides. Volatile fatty acids were found also in the blood of the rabbit, guinea pig, horse, and pig and in human plasma. Here again a high proportion of acetic acid was recorded. Volatile fatty acid isolated from nine samples of ruminal contents from two cows contained on a molecular basis from 52.3 to 69.0 per cent. of acetic acid (mean 60.0 per cent.). The remainder comprised, as mean values, propionic acid, 21.8 per cent.; butyric acid, 14.4 per cent.; and acids higher than butyric (apparently largely valeric and hesanoic), 3.8 per cent. This limited number of analyses indicated no gross effect of type of feed on the proportion of the acids in the rumen.

Nutritional status and intake regulation in sheep. V. Effects of intraruminal infusions of volatile fatty acids upon voluntary intake of roughage by sheep

1966 ◽  
Vol 17 (5) ◽  
pp. 741 ◽  
Author(s):  
AR Egan
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Energy Balance ◽  
Nutritional Status ◽  
Propionic Acid ◽  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Voluntary Intake ◽  
Induced Changes ◽  
Intake Regulation

Results of experiments with infusions of volatile fatty acids into the rumen reveal that the induced changes in voluntary intake of roughages are not immediate, and vary in extent between animals. Single infusions resulted in subsequent depressions of feed intake, these being only partly related to the amount of energy of the infused volatile fatty acids. When longer-term infusions were made, acetic acid in small quantities depressed feed intake more than did propionic, and propionic acid modified the effect of acetic when the two were given together. Also recorded is an observation that animals receiving a casein-supplemented roughage diet reduced their feed intake when casein was infused per duodenum over 14-day periods. Results are discussed in relation to an hypothesis of an indirect mechanism attempting to maintain or restore the original energy balance, but showing considerable delay or inertia and imprecision when observed on a day to day basis.

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