Studies on the production of volatile fatty acids from grass by rumen liquor in an artificial rumen: III. A note on the volatile fatty acid production from crude fibre and grass cellulose

1957 ◽  
Vol 49 (2) ◽  
pp. 180-183 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid

1. The findings presented in two previous papers on the yields of volatile fatty acids, obtained by the action of rumen liquor in the artificial rumen, from fresh grass, dried grass and the water-soluble and water-insoluble separates of the latter, have been amplified by a consideration of the acids similarly obtained from specimens of chemically prepared crude fibre and cellulose, from four of the dried grass specimens.2. The proportions of different volatile fatty acids from grass crude fibre and grass cellulose resemble those obtained from cellulose powder, propionic acid being produced in greatest relative yield.3. A general review of these latter findings, in relation to those already presented, has been given.

RSC Advances ◽  
2015 ◽  
Vol 5 (62) ◽  
pp. 50033-50039 ◽  
Author(s):  
Xue Yang ◽  
Lei Wen ◽  
Xiang Liu ◽  
Si Chen ◽  
Yayi Wang ◽  
...  

Although many pretreatment methods are employed to enhance the hydrolysis of waste activated sludge (WAS), the bioconversion of soluble complex substrates needs improvement to produce higher volatile fatty acids (VFAs).


2021 ◽  
Author(s):  
Gamsathvani Sivanantham

In the following report, the effects of substrate type and pretreatment type on the production of volatile fatty acids during anaerobic digestion was analyzed. First, the effects on volatile fatty acid production due to substrate type were investigated. It was determined that wastes that consisted of higher concentrations of carbohydrates would generate higher concentrations of volatile fatty acids during anerobic digestion. In the investigation it was evident that food waste had higher volatile fatty acid yields compared to sludge due to the carbohydrate content. Furthermore, the effects on volatile fatty acid production due to pretreatment type were also investigated. Thermal, chemical, physical and combined pretreatments were analysed. The various types of the different pretreatments and their effects on volatile fatty acid production during anaerobic digestion were discussed in depth.


2021 ◽  
Author(s):  
Gamsathvani Sivanantham

In the following report, the effects of substrate type and pretreatment type on the production of volatile fatty acids during anaerobic digestion was analyzed. First, the effects on volatile fatty acid production due to substrate type were investigated. It was determined that wastes that consisted of higher concentrations of carbohydrates would generate higher concentrations of volatile fatty acids during anerobic digestion. In the investigation it was evident that food waste had higher volatile fatty acid yields compared to sludge due to the carbohydrate content. Furthermore, the effects on volatile fatty acid production due to pretreatment type were also investigated. Thermal, chemical, physical and combined pretreatments were analysed. The various types of the different pretreatments and their effects on volatile fatty acid production during anaerobic digestion were discussed in depth.


1957 ◽  
Vol 49 (2) ◽  
pp. 171-179 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid

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.


1967 ◽  
Vol 18 (1) ◽  
pp. 107 ◽  
Author(s):  
RA Weller ◽  
FV Gray ◽  
AF Pilgrim ◽  
GB Jones

(1) In sheep fed at 12-hr intervals on roughage diets (lucerne and wheaten hay) total volatile fatty acid production in the rumen has been measured by an isotope dilution procedure based on the infusion of a single 14C-labelled volatile fatty acid. (2) Total and individual acid production has been measured through the infusion of a mixture of 14C-labelled acids in which the proportions of individual acids were such that transfers of 14C by interconversions between the acids were balanced. (3) The findings support the view that the mixture of acids produced in the rumen is similar in composition to that present in the rumen fluid throughout the feeding cycle. Consequently it was possible to determine the production of individual acids by a relatively simple procedure requiring only the infusion of a single 14C-labelled acid and measurement of the concentration of 14C in a composite sample of the acids in the rumen fluid collected throughout the feeding cycle. This procedure is considered suitable for routine use; automatic sampling of rumen fluid still further reduces the work involved. (4) The infusion of certain mixtures of 14C-labelled fatty acids showed that the composition of the acid initially formed in the rumen was acetic 77–83%, propionic 15–18%, and butyric 1–7% according to the diet given and the time elapsed after feeding. From 50 to 80% of the butyric acid in the final volatile acid product was formed from acetic acid. Degradation of 14C-labelled butyrate formed from [1-14C] acetate in the rumen showed 93% of the 14C to be nearly evenly divided between carbon atoms C1 and C3.


Author(s):  
Ganesh K Veluswamy ◽  
Andy Ball ◽  
Richard Dinsdale ◽  
Alan Guwy ◽  
Kalpit Shah

Methane, the final product of methanogenesis during anaerobic digestion is a low value product (0.1$/m3). Concerns over fugitive emissions from methane coupled with recent reduction in costs of solar and...


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