Fermentation of Peptides by Bacteroides ruminicola B ₁ 4

Abstract

The maximum growth rate of Bacteroides ruminicola B14 was significantly improved when either Trypticase or acetate and C4-C5 fatty acids were added to defined medium containing macrominerals, microminerals, vitamins, hemin, cysteine hydrochloride, and glucose. The organism was unable to grow with peptides as the sole energy source, but growth yields from glucose were significantly improved when Trypticase was added to batch cultures containing basal medium, acetate, and C4-C5 volatile fatty acids. During periods of rapid growth, very little peptide was deaminated to ammonia, but after growth ceased there was a linear increase in ammonia. Fifteen grams of Trypticase per liter resulted in maximum ammonia production. In glucose-limited chemostats, ammonia production from peptides was inversely proportional to the dilution rate, and 87% of the variation in ammonia production could be explained by retention time in the culture vessel. Chemostats receiving Trypticase had higher theoretical maximum growth yields and lower maintenance energy expenditures than similar cultures not receiving peptide. Cells from the Trypticase cultures contained more carbohydrate, and this difference was most evident at rapid dilution rates. When corrections were made for cell composition and the amount of peptides that were fermented, it appeared that peptide carbon skeletons could be used for maintenance energy. B. ruminicola B14 was unable to grow on peptides alone because it was unable to utilize peptides at a fast enough rate to meet its maintenance requirement.

The in vitro uptake and metabolism of peptides and amino acids by five species of rumen bacteria

“…This difference may again reflect enhanced deamination in the mixed species' incubations as a means of generating energy when energy-yielding substrates were depleted. This supposition agrees with the findings that the availability of fermentable carbohydrates is an important factor in the utilization of peptides and amino acids by rumen bacteria (Maeng et al 1976;Russell 1983;Russell et al 1983).…”

“…Most in vitro studies of peptide and amino acid utilization by rumen bacteria have been conducted with mixed populations (Wallace and Cotta 1988;Broderick et al 1991 ;Russell et al 1991). Some classical studies with single species of bacteria and peptide substrates were published during the 1960s (Pittman and Bryant 1964;Pittman et al 1967), but virtually nothing further was reported until the 1980s, as exemplified by the work of Russell (1983). Even I988), and in particular, Preuotella (formerly Bacteroides) rurninicola (Pittman and Bryant 1964;Pittman et al 1967;Munn et al 1983;Russell 1983;McKain et al 1992;Newbold et al 1992;Wallace et al 1993).…”

“…Some classical studies with single species of bacteria and peptide substrates were published during the 1960s (Pittman and Bryant 1964;Pittman et al 1967), but virtually nothing further was reported until the 1980s, as exemplified by the work of Russell (1983). Even I988), and in particular, Preuotella (formerly Bacteroides) rurninicola (Pittman and Bryant 1964;Pittman et al 1967;Munn et al 1983;Russell 1983;McKain et al 1992;Newbold et al 1992;Wallace et al 1993). Furthermore, comparative studies, involving a number of bacterial species, have been limited to examinations of either general biological functions, such as growth efficiency (Cotta and Russell 1982), or very specific attributes, such as peptidase activity (Wallace and McKain 1991;McKain et al 1992).…”

A pepD-like peptidase from the ruminal bacterium,Prevotella albensis

“…Peptide breakdown in the rumen is part of a degradation process whereby dietary protein is broken down to ammonia, leading to the inefficient utilisation of dietary amino acids [1,2]. The genus Prevotella plays a significant role in this process [2][3][4][5][6][7][8]. The peptidases of Prevotella albensis M384 have been investigated biochemically [5,9,10], and one, a dipeptidyl peptidase IV (DPP-4), has been cloned and characterised [11].…”

Mathematical estimations of hyper-ammonia producing ruminal bacteria and evidence for bacterial antagonism that decreases ruminal ammonia production

“…Bladen et al [8] concluded that P. ruminicola was probably the most important ammonia-producing ruminal bacterium, but even the best strain (B 1 4) produced ammonia at a relatively slow rate. When carbohydrates were available, virtually all of the amino nitrogen was incorporated into microbial protein and the deamination rate was even slower [32]. Carbohydrate-fermenting ruminal bacteria did not have deamination rates that could explain the ability of MRB to produce ammonia ; however, HAB have been shown to generate ammonia 20-fold faster [33,34].…”