Anaerobic Purine Dissimilation by Washed Suspensions of Bovine Rumen Bacteria1,2

Influence of Calcium and Phosphorus, Lactose, and Salt-to-Moisture Ratio on Cheddar Cheese Quality: Changes in Residual Sugars and Water-Soluble Organic Acids During Ripening

Determination of Organic Acids During the Fermentation and Cold Storage of Yogurt

SUMMARY—Whole eggs containing known amounts of formic, acetic, propionic and butyric (C1‐C4) acids were evaluated using gas‐liquid chromatography (GLC) and AOAC (1960) procedures. Acetic, propionic and butyric acids were recovered from whole egg samples and chromatographed as the acids per se, along with an internal standard. Formic and acetic acids were recovered from whole egg samples and chromatographed as their butyl ester derivatives without an internal standard. Quantitation of butyl formate and butyl acetate was accomplished by comparing the chromatogram peak heights of the butyl esters recovered from the egg samples with the chromatogram peak heights of a known concentration of butyl ester standards. The recovery of acids from whole egg samples by GLC procedures was as accurate, and generally less variable, than by AOAC (1960) procedures. The percentage recovery of acids from whole egg samples using GLC procedures depended on the concentrations of the acids present and was as follows: acetic acid varied from 114 to 100% (low to high concentration); propionic acid varied from 101 to 100% (low to high concentrations); and butyric acid varied from 103 to 99% (low to high concentration). The recovery of formic acid as its butyl ester derivative varied from 104 to 96% (low to high concentration), while the recovery of acetic acid as its butyl ester derivative varied from 102 to 98% (low to high concentration).

Untersuchungen über die rolle der niederen fettsäuren beim anaeroben faulprozess und einblicke in seine biozönose

The use of anaerobic fermentation to produce volatile fatty acids (VFAs) is an environmentally sustainable alternative for cheese whey (CW) valorization. This study evaluates the effect of pH control on the conversion of organic matter to VFAs from CW and assesses VFA recovery using a novel approach based on gas-permeable membranes. VFA bioconversion and composition were studied with initial and sequential control of pH, both in acidic and alkaline conditions. Bioconversion efficiencies for assays with initial pH control were 36% and 45% for acidic and alkaline conditions, respectively. Sequential control of pH resulted in an increase in bioconversion to 54% under acidic conditions. Under acidic conditions, a variety of VFA was produced (mainly butyric, acetic, and propionic acids), while under alkaline conditions the majority was acetic acid. VFA recovery using a novel system of tubular gas-permeable membranes accounted for 15% and 100% of the total VFA from effluent 1 (butyric, acetic, and propionic acids) and effluent 2 (mainly acetic acid), respectively.

Background. The purpose of the study was to assess the functional state of gut microbiota in patients with metabolic-associated fatty liver disease (MAFLD) combined with type 2 diabetes mellitus (T2DM). Materials and methods. The prospective interventional randomized study included 71 patients with MAFLD in combination with T2DM, who were examined and divided into the 2 groups. The first group included 39 people with MAFLD and T2DM without small intestinal bacterial overgrowth (SIBO). The second group consisted of 32 patients with MAFLD in combination with T2DM and SIBO. The control group included 25 practically healthy patients. The content of serum zonulin was determined by enzyme-linked immunosorbent assay (ELISA) using test systems IDK Zonulin ELISA, KR5601. Serum concentration of interleukin (IL) 6 and IL-10 was assessed by the ELISA method using the Human Interleukin 6 and 10 ELISA Kit test systems. The content of short-chain fatty acids in feces was determined by gas chromatography with mass spectrometry in the PerkinElmer Clarus 680 GC Gas Chromatograph. Results. Patients of the first and second groups had an increase in hepatic aminotransferases, total cholesterol, triglycerides, fasting blood glucose, insulin, HOMA-IR, glycosylated hemoglobin, serum zonulin, leptin, IL-6 and liver attenuation coefficient and a decrease in high-density lipoprotein. The results of steatometry revealed a severe degree of hepatic steatosis (S3) in patients with MAFLD combined with T2DM and SIBO and without SIBO. During the quantitative study of the level of butyric acid in feces, it was found to be significantly reduced, by 2.3 times in the first group and by 3.4 times in the second one, compared to the controls (p < 0.001). The content of butyric acid was decreased by 1.4 times in the second group compared to the first one (p < 0.001). When evaluating the level of acetic acid, it was found to be significantly increased compared to the controls, by 1.2 times in the first group and by 1.3 times in the second one (p < 0.001). The concentration of propionic acid was increased by 1.3 times in the first group and by 1.5 times in the second one compared the control group (p < 0.05). When comparing the level of acetic acid, a significant increase by 1.3 times was observed in patients of the first and second groups compared to patients of the control group (p < 0.001). The content of propionic and acetic acids was increased by 1.1 times in the second group compared to patients of the first group (p < 0.05). When analyzing the correlation coefficients in patients with MAFLD combined with T2DM and SIBO and without SIBO, a direct proportional strong correlation was revealed between the levels of butyric, acetic and propionic acids and serum zonulin, IL-6, IL-10. A direct moderate correlation was found between the content of short-chain fatty acids and leptin, indicators of lipid metabolism (total cholesterol, triglycerides), carbohydrate metabolism (fasting blood glucose, HOMA-IR, HbA1c) and inverse weak correlation with high-density lipoprotein. A direct moderate correlation was revealed between levels of short-chain fatty acids and indicators of functional activity of the liver (alanine aminotransferase, aspartate aminotransferase), liver attenuation coefficient in patients with MAFLD combined with T2DM and SIBO and without SIBO. Conclusions. Increased intestinal permeability and hyperleptinemia have been found in patients with МAFLD combined with T2DM and SIBO and without SIBO. When studying the functional state of the gut microbiota, an increase was found in propionic and acetic acids and a decrease in butyric acid, which indicates an increase in the number of Bacteroidetes in the intestine and a decrease in Firmicutes. Patients with MAFLD combined with Т2DM and SIBO and without SIBO had a direct proportional strong correlation between the levels of butyric, acetic and propionic acids and serum zonulin, IL-6, IL-10, which is associated with pro-inflammatory and anti-inflammatory processes in the intestinal mucosa and a violation of the permeability of the intestinal barrier. It was found that concentrations of short-chain fatty acids correlate with indicators of functional activity of the liver (alanine aminotransferase, aspartate aminotransferase), leptin, indicators of carbohydrate and lipid metabolism, degree of hepatic steatosis.

In order to establish the chemical nature of volatile acidic odors produced by Clostridium botulinum during growth, volatile fatty acids were determined by gas chormatography in the cultures of cooked meat broth inoculated with each strain of the six toxin-types. The results were as follows: 1. Acetic, propionic, n-butyric, iso-butyric, n-valeric, iso-valeric (iso-valeric and/or active α-methyl-butyric), and iso-caproic acids were identified in the cultures of type A, B and F. The branched acids except iso-caproic acid were deduced to be the metabolic products derived from some branched amino-acids by “Stickland reaction”. 2. Acetic, propionic, and n-butyric acids were identified in both the cultures of types Cβ and D. A high proportion of propionic acid among the resulting fatty acids suggests that these organisms appear to obtain some of their energy by propionic acid fermentation similar to that displayed by propionibacteria. 3. n-Butyric acid, in higher proportion, as well as acetic acid were identified in the cultures of type E, suggesting that this organism obtains most of its energy by butyric acid fermentation similar to that displayed by butyric acid bacteria. Further the chemical nature of the off-odor of foodstuffs contaminated with botulinal toxin was examined. An abnormally high proportion of n-butyric acid, being responsible for the “butyric” off-odor, was found in home-made “Izushi” of raw fish and rice cake, which had caused an episode of human type E botulism. Also a high proportion of propionic acid, as well as acetic and n-butyric acids were found in raw whale meat, which had caused an outbreak of type Cβ botulism in mink. Accordingly, the patterns of the volatile fatty acids presented by each type of Clostridium botulinum seem to be reflected in that of foodstuffs contaminated with respective type of the organisms.

Liquid swine manure added to acidic soils killed microsclerotia of the wilt fungus Verticillium dahliae. We investigated whether volatile fatty acids (VFAs) in the manure were responsible for this toxicity. The survival of microsclerotia was determined after exposure to various dilutions of manure or its VFA components. Acetic, propionic, and isobutyric acids constituted the major VFAs in the manure, while n-butyric, n-valeric, iso-valeric, and n-caproic acids were present in lesser amounts. Formic acid was not detected. The individual VFAs were more toxic to microsclerotia as the solution pH was decreased, indicating that the protonated forms of the VFAs were toxic (e.g., acetic acid and not acetate). The effective concentration reducing germination of microsclerotia by 95% (EC(95)) for formic and n-caproic acids was approximately 4 mM, the most toxic of the acids tested; for n-valeric, the EC(95) was 9.2 mM, isovaleric was 16.1 mM acids, and acetic, propionic, n-butyric, and isobutyric acids were approximately 30 mM. The toxicity of acetic acid, and likely all the others, was directly related to the duration of exposure. Inhibition of microsclerotia germination followed identical trends in solutions of the manure or in a mixture of VFAs with equivalent concentrations of the individual acids found in the manure. Similarly, germination declined to the same extent in the atmosphere above the manure or the VFA mixture, confirming the toxicity of VFAs to microsclerotia. Thus, under acid conditions, VFAs in liquid swine manure can kill microsclerotia of V. dahliae.

Effects of butyric and acetic acids on acetone-butanol formation by Clostridium acetobutylicum

Background/Objectives: There is a constant increase in the incidence of food allergies. Short-chain fatty acids (SCFAs), responsible for maintaining the intestinal barrier and immune balance, are produced by the intestinal microbiota through the fermentation of dietary fibre. The aim of this systematic literature review was to analyse the association of SCFAs with the occurrence of food allergies. Methods: The analysed data were obtained by searching the PubMed and Scopus databases with the keywords “short-chain fatty acids and allergy”, “SCFA and allergy”, “SCFA and food allergy”, and “acetic acid or propionic acid or butyric acid or 3,4-methylvaleric acid and allergy”. Exclusion criteria were as follows: retracted articles, articles not freely accessible, and incomplete/insufficient data (conference reports). Two authors independently searched the literature. Results: Patients with food allergies show lower levels of SCFAs, especially acetic, butyric and propionic acids. 3,4-methylvaleric acid may be associated with intestinal inflammation in infants and intestinal leakage. Conclusions: Based on studies, there appears to be an association between lower stool levels of SCFAs—particularly butyric, propionic, acetic, and isovaleric acids—and the occurrence of food allergies in both children and adults. A proper diet that strengthens fibre, probiotics, and prebiotics and limits antibiotics, xenobiotics, pesticides is crucial for maintaining adequate SCFA levels and thus reducing allergy-related symptoms. 3,4-Methylvaleric acid and the activation of inflammatory processes contributing to intestinal leakage may provide a new diagnostic path.

Effect of volatile fatty acids on blood flow and oxygen uptake by the dog colon

A selected ion flow tube study of the ion molecule association reactions of protonated (MH+), nitrosonated (MNO+) and dehydroxidated (M−OH)+ carboxylic acids (M) with H2O

The toxicity of four volatile fatty acids (VFAs) as anaerobic digestion (AD) intermediates was investigated at pH 7. Photobacterium phosphoreum T3 was used as an indicator organism. Binary, ternary and mixtures of AD intermediates were designated by letters A (acetic acid + propionic acid), B (acetic acid + butyric acid), C (acetic acid + ethanol), D (propionic acid + butyric acid), E (propionic acid + ethanol), F (butyric acid + ethanol), G (acetic acid + propionic acid + butyric acid), H (acetic acid + propionic acid + ethanol), I (acetic acid + butyric acid+ ethanol), J (propionic acid + butyric acid + ethanol) and K (acetic acid + propionic acid + butyric acid + ethanol) to assess the toxicity through equitoxic mixing ratio method. The IC50 values of acetic acid, propionic acid, butyric acid and ethanol were 9.812, 7.76, 6.717 and 17.33 g/L respectively, displaying toxicity order of: butyric acid > propionic acid > acetic acid > ethanol being additive in nature. The toxic effects of four VFAs could be designated as synergistic and one additive in nature.

Quantitative separation of volatile fatty acids in feces and sewage was examined by gas chromatography, using 5% free fatty acid phase on Chamelite CS as the column packing and a hydrogen flame ionization detector. This method was applied to the examination of the daily variation of volatile fatty acids and BOD in the treated water from each process of night-soil treatment plants. The concentration of total volatile fatty acids in fresh feces was 6700 ppm and they consisted mostly of acetic, propionic, and butyric acids. After a lapse of 19 days, the concentration of total volatile fatty acids amounted to 4600 ppm, and acetic acid occupied 80% of them. Acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids were detected in the samples obtained from the inlet tank and influent. In the effluent, most of them was acetic acid, and propionic acid was in small quantities. In the process of various treatment plants, the tendency for BOD value in the samples to decrease was similar to that of volatile fatty acids, and acetic acid was the main component in the volatile fatty acids.

Low molecular weight chemical compounds or intermediate products of a metabolism or other cellular processes are called metabolites. The objective of the present study was to investigate the variations in the metabolite concentration in the milk from crossbred water Buffalo (B), Holstein cross (H), Indigenous cattle (I) and Red Chittagong Cattle (R) and the relationships among those metabolites. The concentration of citric acid, ? -keto glutaric acid (?-keto GA), orotic acid, pyruvic acid, succinic acid, lactic acid, formic acid, uric acid and propionic acid were measured by using High Performance Liquid Chromatography. Pooled milk samples of nine B, fifteen I and twenty R cows were collected from the research farm of Bangladesh Livestock Research Institute, Savar, Dhaka, Bangladesh. The pooled milk samples of H were collected from twenty five cows of Central Cattle Breeding Station and Dairy Farm, Savar, Dhaka, Bangladesh. All the sampling was done from the morning milking. The samples were preserved by adding ‘bronopol tablet’ and frozen and stored at -20 °C. Except propionic acid, all the metabolites varied significantly (p<0.01) among the milk types and B milk had lowest concentration of them. The highest concentration of citric acid (ppm) was 2245.50±39.90 in I milk followed by 2156.60±26.60 in R, 1858.30±8.70 in H and 1366.70±33.70 in B milk. The H, I and R milk were found similar in their ?-keto GA content. Similarities were also found for succinic acid between H and R milk and so for H and I milk in uric acid content. Highest formic acid was found in H milk (392.78±2.23 ppm) and the lowest was 308.91±3.75 ppm in R milk while B and I milk was found similar. The lowest concentration of uric acid was found 0.44±0.26 ppm in B milk and R milk had the highest content (11.38±1.10 ppm). Pyruvic, formic and propionic acids showed no significant relationship among them and with others as well. The most highly significant (p<0.01) correlation was found between orotic and ?-keto GA (r=0.915) and between uric and succinic acid (r=0.914). So, the metabolites showed a considerable variation in their concentration in different types of milk and also some of the parameters showed significant relationship among them. DOI: http://dx.doi.org/10.3329/bjas.v42i2.18504 Bang. J. Anim. Sci. 2013. 42 (2): 152-157