Analysis of cellulolytic bacterial flora in the rumen of inner Mongolian sheep

Abstract

The cellulolytic bacterial flora present in the rumen of Inner Mongolian sheep are thought to have a high degree of cellulose-degrading activity because of their foraging feeding regimen. However, there are no report on the genetic and species composition of the cellulolytic bacterial flora. In this study, cellulolytic bacteria were isolated from the rumen of Inner Mongolian sheep using a combined method of transparent zone and filter paper degradation. Twenty-two strains were identified via morphological, physiological, and biochemical tests. Ten strains were further identified via DNA (G + C) mol%, together with 16S rDNA gene sequencing analysis. Four types of extracellular and total cellulase activities of representative strains were determined. The results demonstrated that the isolates included Butyrivibrio fibrisolvens, Rumincoccus albus, R. flavefaciens, Fibrobacter succinogenes, and Clostridium polysaccharolyticum. A big proportion of cellulolytic Butyrivibrio fibrisolvens was found in the rumen of Inner Mongolian sheep. This was the first study to analyze the cellulolytic bacterial flora in the rumen of foraging Inner Mongolian sheep. These results indicated that the rumen of Inner Mongolian sheep represents an attractive source for cellulolytic microorganisms and enzymes, and the research results have a certain guiding importance for the efficient degradation of cellulosic materials.

Unraveling aerobic cultivable cellulolytic microorganisms within the gastrointestinal tract of sheep (Ovis aries) and their evaluation for cellulose biodegradation

“…Ruminants and most of herbivores lack the ability to hydrolyze lignocellulose by themselves and instead they can effectively utilize the feed of cellulosic substrates with the aid of cellulolytic and other co-existed microorganisms residing in their GT (Mackie 2002). Accumulating studies have reported the isolates of cellulolytic microbes in GT of ruminants over the previous decades and microbial screening has been extended to a variety of ruminant species, including cattle (Halliwell and Bryant 1963), sheep (Liu et al 2019), camel (Samsudin et al 2012), yak (Cai and Dong 2010), and deer (Park et al 2006).…”

Efecto de la adición de bacterias celulolíticas a bacterias ruminales sobre las características fermentativas in vitro

“…The rumen anaerobic environment and microorganisms make structural carbohydrates digestible (Cai et al, 2010;Sattar et al, 2018;Azizi et al, 2020) by degrading fiber through enzymatic digestion (Berny et al, 2019;Gudeta and Krishna, 2019;Liu et al, 2019). Potential cellulolytic bacteria in the rumen are Bacteroides succinogenes, Clostridium, Trichonympha, Actinomycetes, Butyrivibrio fibrisolvens, Ruminococcus albus and Methanobrevibacter ruminantium (Gudeta and Krishna, 2019).…”

“…CH4 production in the rumen involves an energy loss (Liu et al, 2019;Gang et al, 2020) of between 2 and 12% (Liu et al, 2019). The factors that determine CH4 production are the bromatological characteristics of the substrate and the fermentation products of cellulolytic bacteria (Venegas et al, 2017;Torres-Salado et al, 2019).…”

“…The different values in partial and accumulated production of CH4 among the inocula (Table 1) are due to the NDF content of cobra grass, bacterial conformation of the inocula and production pattern of VFA. Acetate, CO2 and H2 are fermentation products of cellulolytic bacteria (Gang et al, 2020) generating a syntrophic relationship with methanogenic archaea (Liu et al, 2019;Torres-Salado et al, 2019), which use CO2 and H2 as metabolic strategy and produce CH4 (Torres-Salado et al, 2019). This is a consequence of increasing the fermentation of structural carbohydrates since their fermentation by cellulolytic bacteria will always produce CO2 and H2 that the archaea will use.…”