Fermentative Acid Production Research Articles

Changes of Bacterial Numbers and Carbohydrate Fermenting Groups During In Vitro Rumen Incubations with Feedstuff Materials

Short in vitro incubations of mixed ruminal bacteria with feedstuff materials were conducted. In each series of experiments, the rumen bacterial population was divided into equal portions. One portion was washed anaerobically by centrifugation in a mineral buffer prior to initiation of incubation, whereas the other portion was not washed. Changes of carbohydrate group composition of the populations, of bacterial cell composition, and of incubation fluid characteristics were monitored over 24h. Washing the bacterial inoculum did not affect adversely the ensuing feed fermentation and resulted in lower background carbohydrates and fermentation acids. Unwashed bacterial incubations had a greater tendency to produce more lactate. When the feedstuff substrate contained more soluble nutrients, the microbial population exhibited batch culture type growth, and bacteria fermenting soluble carbohydrate predominated. When alfalfa hay was the sole substrate, a more balanced fermentation resulted with respect to both carbohydrate group composition and fermentation acid production. Implications of these findings in relation to use of in vitro methods to estimate digestibility of feedstuff are addressed.

Effects of chetomin on growth and acidic fermentation products of rumen bacteria.

Chetomin, an antibiotic metabolite of Chaetomium spp., was tested in the form of its tetrathiol derivative for its effects on growth and carbohydrate metabolism by five strains of functionally important rumen bacteria. The compound was bacteriostatic for the strains tested and Gram-positive bacteria were more sensitive to inhibition than Gram-negative bacteria. In an anaerobic broth dilution assay using a medium lacking rumen fluid, the minimum inhibitory concentration (MIC) of chetomin which completely inhibited growth of Butyrivibrio fibrisolvens D1 for 18 h at 39 degrees C was 40 micrograms X mL-1. The MICs determined under the same conditions for Megasphaera elsdenii B159, Selenomonas ruminantium GA192, and Succinivibrio dextrinosolvens 24 were 160, 600, and 60 micrograms X mL-1, respectively. The MIC for cellulose hydrolysis by Ruminococcus albus 7 was 20 micrograms X mL-1. Chetomin at concentrations below the MIC appeared to inhibit the separation and division of cells in cultures of B. fibrisolvens D1. Chetomin consistently stimulated acetate production from glucose by B. fibrisolvens D1, M. elsdenii B159, and S. ruminantium GA192 at the expense of compounds which comprised major soluble end products of fermentation in cultures lacking chetomin.

The effect of some pre-ensiling treatments on silage composition and nitrogen disappearance in the rumen

Ryegrass, harvested before ear emergence, was ensiled in triplicate in laboratory silos with and without pre-ensiling treatments. These were: 4.7 M sulphuric acid (39 and 79 g kg −1 DM); formalin (28 and 58 g kg −1 DM); ‘Add-F’ (22.5 M formic acid; 36 and 71 g kg −1 DM); formalin (28 and 58 g kg −1 DM); ‘Farmline’, a commercial additive containing acids and formalin (31 g kg −1 DM); heat (30 and 60°C for 1 h); and Lactobacillus plantarum inoculum + glucose (4.6 g kg −1 DM). The ensilage period was 120 days. Samples of each silage were incubated, in artificial fibre bags, in the rumens of four Hereford-cross steers fitted with permanent rumen cannulae. Total nitrogen (TN) disappearance was measured after incubation periods of 1, 2, 4, 7, 12 and 24 h. Hydrochloric acid and the heating pre-treatments had no significant effect ( P > 0.05) on the pH, water-soluble carbohydrates and fermentation acid values compared with those of the control. Fermentation acid production was suppressed to an increasing extent by formalin (28 g kg −1 DM), sulphuric acid (79 g kg −1 DM), formic acid (36 g kg −1 DM), formalin (58 g kg −1 DM) and formic acid (71 g kg −1 DM). The application of L. plantarum + glucose increased fermentation acids from 90.3 g kg −1 DM in the control to 227 g kg −1 DM, owing to a 10-fold increase in lactic acid content from 21.7 to 202 g kg −1 DM. All treatments, with the exception of 30°C heating, produced silages with significantly ( P < 0.001) more total nitrogen as protein than the control. This ranged from 334 g kg −1 TN (60°C heating) to 748 g kg −1 TN (formalin; 58 g kg −1 DM). All treatments significantly ( P < 0.05) reduced TN loss, compared with the control silage values, after a 7-h incubation period in the rumen. After 24 h, however, TN disappearance from the treated silages was not significantly different from that of the control with the exception of the two silages treated with formalin alone. With these silages, the proportion of TN disappearing was 55.0 and 40.0% for the low and high application rates, respectively, compared with a value of 74.0% for the control.

Fermentative Production of Pyruvic Acid from Citrus Peel Extract byDebaryomyces coudertii

Fermentative production of pyruvic acid by yeasts was studied using extracts from citrus natsudaidai peel as a carbon source. Many yeasts showed good growth. Of these yeasts, Debaryomyces coudertii IFO 1381 produced pyruvic acid at high yield. Pretreatment of the peel extract with Amberlite IR-120B (Na+) led to increased production of pyruvic acid. Under optimum conditions, the accumulation of pyruvic acid reached a maximum of 970 mg/100ml at 48 hr-fermentation. The pyruvic acid from the fermentation broth was identified with lactic acid dehydrogenase and by comparisons of properties of its 2,4-dinitrophenylhydrazone with those of authentic pyruvic acid in paper chromatography, IR spectrometry and elemental analysis.

A rapid gas chromatographic method for the analysis of acidic fermentation products

A rapid and simple method for the identification of acidic fermentation products is described. Methyl esters of volatile and non-volatile acids are separated on a single chromatographic column. Retention time data for a number of acids are tabulated.

Fermentative production of pyruvic acid from citrus peel extract by Debaryomyces coudertii.

Fermentative production of pyruvic acid by yeasts was studied using extracts from citrus natsudaidai peel as a carbon source. Many yeasts showed good growth. Of these yeasts, Debaryomyces coudertii IFO 1381 produced pyruvic acid at high yield. Pretreatment of the peel extract with Amberlite IR-120B (Na+) led to increased production of pyruvic acid. Under optimum conditions, the accumulation of pyruvic acid reached a maximum of 970 mg/100ml at 48 hr-fermentation. The pyruvic acid from the fermentation broth was identified with lactic acid dehydrogenase and by comparisons of properties of its 2,4-dinitrophenylhydrazone with those of authentic pyruvic acid in paper chromatography, IR spectrometry and elemental analysis.

Fermentative Production of Lactic Acid in Presence of some Trace Elements

An attempt was made to study the activity of Lactobacillus delbrueckii under the influence of certain trace elements, viz. Tl, U, Th, and Zr. From the results, it was inferred that Tl has comparatively more stimulating effect on the acid-producing activity of the bacteria than U, Th, and Zr.

Growth inhibition of glucose-grown cariogenic and other streptococci by saccharin in vitro.

Abstract Sodium saccharin in concentrations from 0.02 to 20.00 mg/ml inhibits the in vitro growth of glucose-grown cariogenic and other streptococci, and suppresses, esp. at the higher concentration range, the fermentative acid production of these microorganism s to acid levels much lower than the critical pH of 5.5. These observations indicate a possible caries antagonism by saccharin.

Trichinosis: Physiologic Factors Possibly Altering the Course of Infection

The relative importance, degree of interplay, and mode of action of immunoglobulins and delayed and immediate hypersensitivity in immunity to Trichinella spiralis is not clear. Since several workers have demonstrated the immunogenic nature of antibodies through passive transfer of serum, attempts were made to elucidate a mechanism of action. The direct effect of sera from trichinellainfected rabbits and rats on trichinella larvae were studied with regard to (1) glucose absorption, (2) glucose assimilation, (3) utilization of endogenous carbohydrates, and (4) production of fermentation acids. There was no significant difference in U-14C glucose uptake, tissue labeling patterns, glycogen and trehalose depletion, and acid excretion between control larvae and larvae exposed to immune serum for 48 hr. Specific changes associated with inflamed tissue, such as a reduction in 02 and CO2 tensions, and an increase in hydrogen ion concentration were studied with regard to their importance to worm survival in vitro. The effects of reduced 02 and CO2 tensions on the viability of larvae were inconclusive. In contrast the survival of worms exposed to an acid pH was decreased. Larvae and postlarval worms (recovered from the intestine 24 to 96 hr after infection) maintained for 48 hr at pH 6.0 to 6.5 were less than 50% as viable as controls maintained at a higher pH. Results support the conclusion that antiserum does not directly damage trichinella but may adversely affect the parasite by inducing the development of local acidosis through immunologically mediated inflammation. Such a condition may be involved in worm expulsion during the intestinal phase of trichinosis. Hosts infected with Trichinella spiralis develop a degree of immunity that is dependent in part on reactions leading to the expulsion of the intestinal stages (Denham, 1966; Larsh, 1963, 1968; Despommier and Wostmann, 1968; Denham, 1969). The stage initially contacting defense mechanisms of the host is the infective larva which excysts in the upper gastrointestinal tract and then penetrates the mucosa of the small intestine. Larsh (1963) compared the development of a population of larvae following primary and challenge infections, and observed that with the challenge inoculum some worms developed into stunted adults, fecundity of adult worms was reduced, and intestinal stages were expelled earlier than in control animals. The results suggest that there are nutritional and metabolic disturbances in growing worms that are associated with immune reactions. Received for publication 20 October 1972. * Work was supported by PHS Research Grants AI09348 and AI08491 and Research Fellowship GM44959 from the NIH, and Grant GY2436 from the NSF. t Present address: Program in Physiology, The University of Texas Medical School, Houston, Texas 77025. + Present address: St. Jean's Convent, 196 E. 76 Street, New York, New York 10021. Although acquired resistance to helminths involves more than direct antigen-antibody reactions (Soulsby, 1962; Larsh, 1967, 1968; Tanner, 1968; Gore et al., 1970; Thorson, 1970), immunoglobulins have been implicated in immunity to trichinella (Culbertson and Kaplan, 1938; Oliver-Gonzalez, 1941; Culbertson, 1942; Hendricks, 1953). It is not clear whether antibodies affect the parasite directly. Adverse effects on intestinal stages of trichinella in challenged animals have also been attributed, in part, to an immunologically mediated inflammatory response in the gut mucosa which is unsuitable for worm survival (Larsh, 1967). However, specific conditions associated with inflammation, such as a reduction in oxygen or carbon dioxide, or an increase in hydrogen ion concentration (Menkin, 1956) have not been studied. In the present investigation the following hypotheses were tested: (1) that immune serum, or gamma globulins in such serum, adversely affect the uptake and metabolism of glucose, and (2) that specific alterations in pH and in CO2 and 02 tensions impair the ability of the parasite to survive and thus contribute to acquired resistance.

Fermentative Production of Succinic Acid from n-Paraffin by Candida brumptii IFO 0731

An investigation of succinic acid production from n-paraffin under various culture conditions was carried out with Candida brumptii IFO 0731. Ammonium nitrogen was required for both cell growth and succinic acid production. Favorable culture conditions for succinic acid production were ascertained. The productivity was markedly increased by the additions of CaCO3 and organic nutrients. Under the best condition, the largest quantity of succinic acid production, 23.6 mg/ml, was obtained in a 67% yield from super heavy n-paraffin after 8 days cultivation.

Quantitative ether extraction of acidic fermentation products.

Quantitative ether extraction of acidic fermentation products.

Preparation of extracts of culture liquids for gas-chromatographic determination of acidic fermentation products

An extraction method coupled with gas-chromatographic analysis has been devised for the determination of small amounts of C1-C7 branched and straight-chain saturated fatty acids as well as 18 mono-, di- and tricarboxylic acids and related compounds, the latter being analyzed either as their methylesters or as their trimethylsilyl-derivatives. Methods for extracting non-volatile acids or both volatile and non-volatile acids are described for large and small volumes of culture media. The proposed methods have been successfully applied to the determination of non-acidic fermentation products, known amounts of alcohols, and to volatile and non-volatile acids in bacterial fermentation solutions, namely a batch culture ofLactobacillus casei subsp.rhamnosus ATCC 7469. A carbon balance sheet of this organism's metabolic behaviour throughout growth is proposed.

Fermentative Production of L-Glutamic Acid from α-Ketoglutaric Acid and Ammonium Sait

Fermentative Production of L-Glutamic Acid from α-Ketoglutaric Acid and Ammonium Sait

Effect of carbohydrates on aspartic acid deaminase activity of bacteria.

Summary1. The reduction in aspartic acid deaminase activity in cells harvested from a medium containing glucose has been shown not to be specific to this sugar, but rather is shared by other fermentable carbohydrates. 2. The effect of the carbohydrate varies among the several strains studied, and is not associated with the increase in hydrogen ion concentration due to the production of fermentation acids.

Oxidation-reduction processes in cultures of bacteria II. Anaerobic growth of Bact. lactis aerogenes

A survey is made of the carbon sources which will support anaerobic growth of Bact. lactis aerogenes . In all cases where it occurs this is slower than aerobic growth, and entails a greater consumption of the substrate (Pasteur effect). A special study has been made of the phenomena attending the transition from aerobic to anaerobic growth and vice versa. The former transition is accompanied by marked discontinuities. During arrested multiplication there is an enhancement of reducing power, which returns approximately to the original (aerobic) value if anaerobic growth supervenes. In glucose cultures the production of acid now increases several times. The adjustments which these effects indicate require the presence of a nitrogen source for their completion. On the other hand, little adjustment is required for the reverse transition, and the cells apparently retain unimpaired the ability to consume molecular oxygen at the optimum rate as soon as it is again offered. The fermentative production of acid is immediately cut by aeration, even in the absence of any nitrogen source. The various detailed observations are interpreted in the light of the hypothesis that the major adjustment in the transition to anaerobic conditions is the development of a new mechanism for the re-oxidation of reduced hydrogen carriers previously dealt with by the molecular oxygen system. This new process involves extra wasteful consumption of substrate. Its development requires enzymatic adjustments. On the other hand, re-aeration cuts down the fermentative processes by simple lowering of the concentrations of the reduced hydrogen carriers involved.

Oxidation-reduction processes in cultures of bacteria. II. Anaerobic growth of Bact. lactis aerogenes.

A survey is made of the carbon sources which will support anaerobic growth of Bact. lactis aerogenes . In all cases where it occurs this is slower than aerobic growth, and entails a greater consumption of the substrate (Pasteur effect). A special study has been made of the phenomena attending the transition from aerobic to anaerobic growth and vice versa. The former transition is accompanied by marked dis­continuities. During arrested multiplication there is an enhancement of reducing power, which returns approximately to the original (aerobic) value if anaerobic growth supervenes. In glucose cultures the production of acid now increases several times. The adjustments which these effects indicate require the presence of a nitrogen source for their completion. On the other hand, little adjustment is required for the reverse transition, and the cells apparently retain unimpaired the ability to consume molecular oxygen at the optimum rate as soon as it is again offered. The fermentative production of acid is immediately cut by aeration, even in the absence of any nitrogen source. The various detailed observations are interpreted in the light of the hypothesis that the major adjustment in the transition to anaerobic conditions is the development of a new mechanism for the reoxidation of reduced hydrogen carriers previously dealt with by the molecular oxygen system. This new process involves extra wasteful consumption of substrate. Its development requires enzymatic adjustments. On the other hand, re-aeration cuts down the fermentative processes by simple lowering of the concentrations of the reduced hydrogen carriers involved.