Pectin-fermenting Bacteria Isolated from the Bovine Rumen

Abstract

Thirty-two strains of pectin-fermenting rumen bacteria were isolated from bovine rumen contents in a rumen fluid medium which contained pectin as the only added energy source. Based on differences in morphology and the Gram stain, 10 of these strains were selected for characterization. Two strains were identified as Lachnospira multiparus, four strains were identified as Butyrivbrio fibrisolvens, and three strains were identified as Bacteroides ruminicola. Characteristics of the remaining strain did not correspond with any previously described species. It was a gram-positive anaerobic coccus, 1.0 to 1.2,um in diameter, and occurred primarily as single cells or diplococci. The strain fermented pectin rapidly but showed little or no growth on any other energy sources tested. The only detectable end products were acetic acid and gas, a portion of which was identified as hydrogen. Although the physiological characteristics of this organism differ markedly from other described species, it has been placed in the genus Peptostreptococcus on the basis of morphology, Gram stain, relations to oxygen, and the occurrence of cell division in only one plane. End products of fermentation are somewhat similar to those of the cellulolytic ruminococci. Eight previously characterized strains of cellulolytic bacteria isolated in nonselective media were unable to ferment pectin, whereas ten strains of hemicellulolytic rumen bacteria, eight of which were isolated with a xylan medium, showed considerable variation in this characteristic.

Degradation and utilization of forage hemicellulose by rumen bacteria, singly in coculture or added sequentially

“…One additional factor to be considered is whether the enzymatic capabilities of rumen bacteria on isolated substrates are applicable to these same substrates as they occur in the forage. Dehority (1969) observed no increase in optical density when P. ruminicola H2b was grown in a medium with isolated citrus pectin as the sole energy source, and on this basis classified the strain as nonpectinolytic. However, Osborne and Dehority (1989) found that P .…”

“…The anaerobic culture techniques used were those of Hungate (1950), with the modifications of Dehority (1969). The media, containing 0.75% forage, was prepared, dispensed and inoculated as described by Coen and Dehority (1970).…”

Growth and pectate-lyase activity of the ruminal bacterium Lachnospira multiparus in the presence of short-chain organic acids

“…The capacity of L. multiparus to degrade pectin and the role of this bacterium in the rumen environment have been well established (Clarke et al 1969;Dehority 1969). A study on the Entner-Doudoroff pathway of L. multiparus has been performed (Dušková and Marounek 2001) but the key fermentative enzymes are not known.…”

“…Lachnospira multiparus degrades pectin, and tetramers, trimers and dimers of galacturonic acid to the corresponding monomers (Wojciechowicz et al 1980). Although L. multiparus cannot use galacturonic acid as a carbon source (Dehority 1969;Tomerska and Wojciechowicz 1973), the products of the hydrolysis of pectic substances by this bacterium can be used by other ruminal microorganisms such as Selenomonas ruminantium, Fusobacterium sp, Eubacterium ruminantium and Succinivibrio dextrinosolvens (Tomerska and Wojciechowicz 1973). The predominant pectinolytic enzyme present in L. multiparus is pectate lyase (PL), but a polygalacturonase activity is also present and both enzymes are constitutive (Wojciechowicz et al 1980;Dušková and Marounek 2001).…”

Identification of a novel adenylate cyclase in the ruminal anaerobe, Prevotella ruminicola D31d

“…Organisms, plasmids, and media P. ruminicola D31d was obtained from B.A. Dehority, The Ohio State University [7]. Recent taxonomic changes for Prevotella species have been proposed [8]; strain D31d, on the basis of DNA-DNA relatedness to the type strain P. ruminicola 23 [9], is considered to be P. ruminicola.…”