Simulating Rumen Conditions Using an Anaerobic Dynamic Membrane Bioreactor to Enhance Hydrolysis of Lignocellulosic Biomass.

An anaerobic dynamic membrane bioreactor (AnDMBR) mimicking rumen conditions was developed to enhance the hydrolysis of lignocellulosic materials and the production of volatile fatty acids (VFAs) when treating food waste. The AnDMBR was inoculated with cow rumen content and operated at a 0.5 day hydraulic retention time, 2-4 day solids retention time, a temperature of 39 °C, and a pH of 6.3, characteristics similar to those of a rumen. Removal rates of neutral detergent fiber and acid detergent fiber of 58.9 ± 8.4 and 69.0 ± 8.6%, respectively, and a VFA yield of 0.55 ± 0.12 g VFA as chemical oxygen demand g volatile solids (VS)fed-1 were observed at an organic loading rate of 18 ± 2 kg VS m-3 day-1. The composition and activity of the microbial community remained consistent after biofilm disruption, bioreactor upset, and reinoculation. Up to 66.7 ± 5.7% of the active microbial populations and 51.0 ± 7.0% of the total microbial populations present in the rumen-mimicking AnDMBR originated from the inoculum. This study offers a strategy to leverage the features of a rumen; the AnDMBR achieved high hydrolysis and fermentation rates even when treating substrates different from those fed to ruminants.

Influence of Nigella sativa seeds, Rosmarinus officinalis leaves and their combination on growth performance, immune response and rumen metabolism in Dorper lambs.

The objective of this study was to determine the effects of dietary supplementation of Nigella sativa L. seeds, Rosmarinus officinalis L. leaves and their combination on rumen metabolism, nutrient intake and digestibility, growth performance, immune response and blood metabolites in Dorper lambs. Twenty-four entire male Dorper lambs (18.68 ± 0.6 kg, 4-5 months old) were randomly assigned to a concentrate mixture containing on a dry matter basis either, no supplement (control, T1), 1% R. officinalis leaves (T2), 1% N. sativa seeds (T3) or 1% R. officinalis leaves +1% N. sativa seeds (T4). The lambs had ad libitum access to urea-treated rice straw (UTRS) and were raised for 90 days. Supplemented lambs had greater (P < 0.05) intake of DM and UTRS than the control lambs. The T4 lambs had lower (P < 0.05) nutrient digestibility than those fed other treatments. Total and daily weight gain was greater (P < 0.05) in T2 lambs than those fed other diets. The T3 and T4 lambs had greater (P < 0.05) ruminal pH than the T1 and T2 lambs. Supplemented lambs had lower (P < 0.05) ruminal total volatile fatty acids, acetate, propionate, NH3-N and C18:0 than the control lambs. The T4 lambs had lower (P < 0.05) population of Fibrobacter succinogenes, Ruminococcus albus, methanogens and total protozoa compared with those fed other diets. Supplemented lambs had lower (P < 0.05) neutrophils, basophils and serum urea and greater (P < 0.05) serum IgA and IgG compared with the control lambs. The current results emphasised the variation in the efficacy of medicinal plants in ruminant nutrition.

Effects of dietary supplementation of leaves and whole plant of Andrographis paniculata on rumen fermentation, fatty acid composition and microbiota in goats.

BACKGROUND: The nature and amount of dietary medicinal plants are known to influence rumen fermentation and nutrient digestibility in ruminants. Nonetheless, changes in nutrient digestibility and rumen metabolism in response to dietary Andrographis paniculata (AP) in goats are unknown. This study examined the effects of dietary supplementation of leaves and whole plant of AP on nutrient digestibility, rumen fermentation, fatty acids and rumen microbial population in goats. Twenty-four Boer crossbred bucks (4 months old; average body weight of 20.18 ± 0.19 kg) were randomly assigned to three dietary groups of eight goats each. The dietary treatments included a control diet (Basal diet without additive), basal diet +1.5% (w/w) Andrographis paniculata leaf powder (APL) and basal diet +1.5% (w/w) Andrographis paniculata whole plant powder (APW). The trial lasted 100 d following 14 d of adjustment. RESULTS: The rumen pH and concentration of propionate were greater (P < 0.05) in goats fed the APL and APW diets than those fed the control diet. The concentrations of ammonia nitrogen and acetate were greater (P < 0.05) in the control goats than the APL and APW goats. The digestibilities of crude protein, dry matter, acid detergent fibre and neutral detergent fibre were greater (P < 0.05) in the APL and APW goats compared to the control goats. Dietary APL and APW decreased (P < 0.05) the ruminal concentration of C18:0 and increased (P < 0.05) the ruminal concentration of C18:2n-6 and C18:3n-3. The APL goats had greater (P < 0.05) ruminal concentration of C18:1 trans-11 and CLA cis-9 trans-11 than the APW and control goats. Dietary treatments had no significant effect on the population of protozoa and methanogens in the rumen of goats. The ruminal populations of Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes were greater (P < 0.05) in the APL and APW goats than the control goats. CONCLUSION: Dietary supplementation of leaves and whole plant of Andrographis paniculata can be used to manipulate rumen metabolism for improved nutrient digestibility in goats.

Polyclonal antibodies inhibit growth of key cellulolytic rumen bacterial species.

Antibodies targeting specific bacterial species could allow for modification of the rumen microbial population to enhance rumen fermentation. However, there is limited knowledge of targeted antibody effects on rumen bacteria. Therefore, our objective was to develop efficacious polyclonal antibodies to inhibit the growth of targeted cellulolytic bacteria from the rumen. Egg-derived, polyclonal antibodies were developed against pure cultures of Ruminococcus albus 7 (anti-RA7), Ruminococcus albus 8 (anti-RA8), and Fibrobacter succinogenes S85 (anti-FS85). Antibodies were added to a cellobiose-containing growth medium for each of the three targeted species. Antibody efficacy was determined via inoculation time (0 h and 4 h) and dose response. Antibody doses included: 0 (CON), 1.3 × 10-4 (LO), 0.013 (MD), and 1.3 (HI) mg antibody per ml of medium. Each targeted species inoculated at 0 h with HI of their respective antibody had decreased (P < 0.01) final optical density and total acetate concentration after a 52 h growth period when compared with CON or LO. Live/dead stains of R. albus 7 and F. succinogenes S85 dosed at 0 h with HI of their respective antibody indicated a decrease (≥ 96%; P < 0.05) in live bacterial cells during the mid-log phase compared with CON or LO. Addition of HI of anti-FS85 at 0 h in F. succinogenes S85 cultures reduced (P < 0.01) total substrate disappearance over 52 h by at least 48% when compared with CON or LO. Cross-reactivity was assessed by adding HI at 0 h to non-targeted bacterial species. Addition of anti-RA8 or anti-RA7 to F. succinogenes S85 cultures did not affect (P ≥ 0.45) total acetate accumulation after 52 h incubation, indicating that antibodies have less of an inhibitory effect on non-target strains. Addition of anti-FS85 to non-cellulolytic strains did not affect (P ≥ 0.89) OD, substrate disappearance, or total VFA concentrations, providing further evidence of specificity against fiber-degrading bacteria. Western blotting with anti-FS85 indicated selective binding to F. succinogenes S85 proteins. Identification by LC-MS/MS of 8 selected protein spots indicated 7 were outer membrane proteins. Overall, polyclonal antibodies were more efficacious at inhibiting the growth of targeted cellulolytic bacteria than non-targeted bacteria. Validated polyclonal antibodies could serve as an effective approach to modify rumen bacterial populations.

Effects of Different Yeast Selenium Levels on Rumen Fermentation Parameters, Digestive Enzyme Activity and Gastrointestinal Microflora of Sika Deer during Antler Growth.

The aim of this experiment was to study the effects of different selenium supplemental levels on rumen fermentation microflora of sika deer at the velvet antler growth stage. A total of 20 5-year-old, healthy sika deer at the velvet antler growth stage with an average body weight of (98.08 ± 4.93) kg were randomly divided into 4 groups, and each group was fed in a single house. The SY1 group was the control group, and the SY2 group, SY3 group and SY4 group were fed a basal diet supplemented with 0.3, 1.2 and 4.8 mg/kg selenium, respectively. The pretest lasted for 7 days, and the formal trial period lasted for 110 days. The results show that: At the velvet antler growth stage, the digestibility of neutral detergent fiber and acid detergent fiber of sika deer in the SY2 group was significantly higher than that in the control group (p < 0.01). The digestibility of cellulose and crude fiber of sika deer in the SY2 group was significantly higher than those in the SY3 and SY4 groups (p < 0.01) and significantly higher than that in the control group (p < 0.05). The contents of acetic acid and propionic acid in the rumen fluid of sika deer in the SY2 group were significantly higher than those in the SY1 group (p < 0.05). Digestive enzyme analysis of rumen fluid at the velvet antler growth stage showed that the activity of protease in rumen fluid in the SY2 group was significantly lower than those in the SY1 group and SY4 group (p < 0.05). The relative abundance of Fibrobacter succinogenes in the SY2 group was significantly higher than that in the SY1 group (p < 0.05) and extremely significantly higher than those in the SY3 and SY4 groups (p < 0.01). Correlation analysis between yeast selenium level and bacterial abundance showed that the yeast selenium content in rumen fluid was significantly positively correlated with Butyrivibrio and Succiniclasticum (p < 0.01). Further verification of bacterial flora functioning showed that the SY2 group was more inclined to the degradation and utilization of fiber. In conclusion, 0.3 mg/kg selenium supplementation can increase the abundance of Prevotella ruminicola and Fibrobacter succinogenes in the rumen of sika deer and improve the degradation of fibrous substances by mediating the catabolite repression process.

Cellulolytic bacteria in the large intestine of mammals.

The utilization of dietary cellulose by resident bacteria in the large intestine of mammals, both herbivores and omnivores (including humans), has been a subject of interest since the nineteenth century. Cellulolytic bacteria are key participants in this breakdown process of cellulose, which is otherwise indigestible by the host. They critically contribute to host nutrition and health through the production of short-chain fatty acids, in addition to maintaining the balance of intestinal microbiota. Despite this key role, cellulolytic bacteria have not been well studied. In this review, we first retrace the history of the discovery of cellulolytic bacteria in the large intestine. We then focus on the current knowledge of cellulolytic bacteria isolated from the large intestine of various animal species and humans and discuss the methods used for isolating these bacteria. Moreover, we summarize the enzymes and the mechanisms involved in cellulose degradation. Finally, we present the contribution of these bacteria to the host.

The Phylogenomic Diversity of Herbivore-Associated Fibrobacter spp. Is Correlated to Lignocellulose-Degrading Potential.

Members of the genus Fibrobacter are cellulose-degrading bacteria and common constituents of the gastrointestinal microbiota of herbivores. Although considerable phylogenetic diversity is observed among members of this group, few functional differences explaining the distinct ecological distributions of specific phylotypes have been described. In this study, we sequenced and performed a comparative analysis of whole genomes from 38 novel Fibrobacter strains against the type strains for the two formally described Fibrobacter species F. succinogenes strain S85 and F. intestinalis strain NR9. Significant differences in the number of genes encoding carbohydrate-active enzyme families involved in plant cell wall polysaccharide degradation were observed among Fibrobacter phylotypes. F. succinogenes genomes were consistently enriched in genes encoding carbohydrate-active enzymes compared to those of F. intestinalis strains. Moreover, genomes of F. succinogenes phylotypes that are dominant in the rumen had significantly more genes annotated to major families involved in hemicellulose degradation (e.g., CE6, GH10, and GH43) than did the genomes of F. succinogenes phylotypes typically observed in the lower gut of large hindgut-fermenting herbivores such as horses. Genes encoding a putative urease were also identified in 12 of the Fibrobacter genomes, which were primarily isolated from hindgut-fermenting hosts. Screening for growth on urea as the sole source of nitrogen provided strong evidence that the urease was active in these strains. These results represent the strongest evidence reported to date for specific functional differences contributing to the ecology of Fibrobacter spp. in the herbivore gut.IMPORTANCE The herbivore gut microbiome is incredibly diverse, and a functional understanding of this diversity is needed to more reliably manipulate this community for specific gain, such as increased production in ruminant livestock. Microbial degraders of plant cell wall polysaccharides in the herbivore gut, particularly Fibrobacter spp., are of fundamental importance to their hosts for digestion of a diet consisting primarily of recalcitrant plant fibers. Considerable phylogenetic diversity exists among members of the genus Fibrobacter, but much of this diversity remains cryptic. Here, we used comparative genomics, applied to a diverse collection of recently isolated Fibrobacter strains, to identify a robust association between carbohydrate-active enzyme gene content and the Fibrobacter phylogeny. Our results provide the strongest evidence reported to date for functional differences among Fibrobacter phylotypes associated with either the rumen or the hindgut and emphasize the general significance of carbohydrate-active enzymes in the evolution of fiber-degrading bacteria.

A global analysis of gene expression in Fibrobacter succinogenes S85 grown on cellulose and soluble sugars at different growth rates.

BACKGROUND: Cellulose is the most abundant biological polymer on earth, making it an attractive substrate for the production of next-generation biofuels and commodity chemicals. However, the economics of cellulose utilization are currently unfavorable due to a lack of efficient methods for its hydrolysis. Fibrobacter succinogenes strain S85, originally isolated from the bovine rumen, is among the most actively cellulolytic mesophilic bacteria known, producing succinate as its major fermentation product. In this study, we examined the transcriptome of F. succinogenes S85 grown in continuous culture at several dilution rates on cellulose, cellobiose, or glucose to gain a system-level understanding of cellulose degradation by this bacterium. RESULTS: Several patterns of gene expression were observed for the major cellulases produced by F. succinogenes S85. A large proportion of cellulase genes were constitutively expressed, including the gene encoding for Cel51A, the major cellulose-binding endoglucanase produced by this bacterium. Moreover, other cellulase genes displayed elevated expression during growth on cellulose relative to growth on soluble sugars. Growth rate had a strong effect on global gene expression, particularly with regard to genes predicted to encode carbohydrate-binding modules and glycoside hydrolases implicated in hemicellulose degradation. Expression of hemicellulase genes was tightly regulated, with these genes displaying elevated expression only during slow growth on soluble sugars. Clear differences in gene expression were also observed between adherent and planktonic populations within continuous cultures growing on cellulose. CONCLUSIONS: This work emphasizes the complexity of the fiber-degrading system utilized by F. succinogenes S85, and reinforces the complementary role of hemicellulases for accessing cellulose by these bacteria. We report for the first time evidence of global differences in gene expression between adherent and planktonic populations of an anaerobic bacterium growing on cellulose at steady state during continuous cultivation. Finally, our results also highlight the importance of controlling for growth rate in investigations of gene expression.

Diauxic growth of Fibrobacter succinogenes S85 on cellobiose and lactose.

Fibrobacter succinogenes rapidly colonizes the preruminant calf rumen and becomes a dominant cellulolytic bacterium in the rumen after weaning. Although F. succinogenes actively degrades cellulose in the rumen, it seems that there is no or little of its substrate, cellulose, in the rumen of preweaned calves. We thus evaluated the ability of F. succinogenes to utilize lactose, a main sugar of milk, with or without the presence of cellobiose. We grew F. succinogenes S85 on media containing 2.5% lactose combined with 0%-0.2% cellobiose or a medium with 0.2% cellobiose but without lactose. The generation times on the 0.2% cellobiose medium and the 2.5% lactose medium were 1.9 and 16.2 h, respectively. The bacterium showed rapid growth on cellobiose and diauxic growth on the lactose media containing 0.05%-0.2% cellobiose. Moreover, the production of ß-galactosidase was low in the presence of 0.1%-0.2% cellobiose. Since the ß-galactosidase contained a signal peptide and a Por secretion system C-terminal sorting domain, we speculate that the ß-galactosidase would be secreted from the bacterial cells by the Por secretion system. Our data indicate the possibility that F. succinogenes could colonize preruminant calf rumen, consuming the lactose present in cow milk.

Lignocellulose-Degrading Microbial Communities in Landfill Sites Represent a Repository of Unexplored Biomass-Degrading Diversity.

The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have focused predominantly on the animal gut, biomass-degrading communities in landfill sites represent an unexplored resource of hydrolytic enzymes for biomass conversion. Here, to address the paucity of information on biomass-degrading microbial diversity beyond the gastrointestinal tract, cellulose (cotton) "baits" were incubated in landfill leachate microcosms to enrich the landfill cellulolytic microbial community for taxonomic and functional characterization. Metagenome and 16S rRNA gene amplicon sequencing demonstrated the dominance of Firmicutes, Bacteroidetes, Spirochaetes, and Fibrobacteres in the landfill cellulolytic community. Functional metagenome analysis revealed 8,371 carbohydrate active enzymes (CAZymes) belonging to 244 CAZyme families. In addition to observing biomass-degrading enzymes of anaerobic bacterial "cellulosome" systems of members of the Firmicutes, we report the first detection of the Fibrobacter cellulase system and the Bacteroidetes polysaccharide utilization locus (PUL) in landfill sites. These data provide evidence for the presence of multiple mechanisms of biomass degradation in the landfill microbiome and highlight the extraordinary functional diversity of landfill microorganisms as a rich source of biomass-degrading enzymes of potential biotechnological significance. IMPORTANCE The microbial conversion of lignocellulosic biomass for biofuel production represents a renewable alternative to fossil fuels. However, the discovery of new microbial enzymes with high activity is critical for improving biomass conversion processes. While attempts to identify superior lignocellulose-degrading enzymes have focused predominantly on the animal gut, biomass-degrading communities in landfill sites represent an unexplored resource of hydrolytic enzymes for biomass conversion. Here, we identified Firmicutes, Spirochaetes, and Fibrobacteres as key phyla in the landfill cellulolytic community, detecting 8,371 carbohydrate active enzymes (CAZymes) that represent at least three of the recognized strategies for cellulose decomposition. These data highlight substantial hydrolytic enzyme diversity in landfill sites as a source of new enzymes for biomass conversion.

Comprehensive detection of bacterial carbohydrate-active enzyme coding genes expressed in cow rumen.

To find the abundant and characteristic fibrolytic enzyme-coding gene expressed in fiber-associating microbiota, a metatranscriptomic data set was obtained from fiber-associating microbiota, and it was compared with that of rumen fluid-floating microbiota and two metagenomic data sets. Fibrolytic rumen bacteria associate with plant polysaccharide and hydrolyze it in the rumen. We obtained a metatranscriptomic assembly from fiber-associating microbiota in three ruminally fistulated Holstein cows fed timothy (Phleum pratense) hay. Each metatranscriptomic data set involved over a thousand of the glycoside hydrolase (GH) gene transcripts that accounted for about 1% of total protein coding gene transcripts. Three-quarters of the total GH gene transcripts were dominated by non-structural oligosaccharide-acting hydrolase gene transcripts. In the fiber-associating microbiota, endo-cellulase coding gene families, especially GHs 9 and 5, were abundantly detected, and GHs 9, 11, 30 and 43, carbohydrate esterase 8 and carbohydrate-binding module 6 were characteristically detected. Most fibrolytic gene transcripts assigned to Fibrobacter succinogenes were detected in fiber-associating sections, and GHs 45, 44, 74, 11, 30 and 16 were Fibrobacter-characteristically detected. The metatranscriptomic assembly highlighted the characteristic fibrolytic enzymes expressed in the fiber-associated rumen microbiota and offered access to the fibrolytic activities in each fibrolytic bacteria.

Determination of bacteria constituting ruminal fibrolytic consortia developed on orchard grass hay stem.

To determine the relationship between Fibrobacter succinogenes and other rumen bacteria, the bacterial community structure on fiber was analyzed by using two different materials. These were ruminally incubated orchard grass hay stems without and with preincubation with F. succinogenes (natural and artificial consortia, respectively). The natural consortium mainly consisted of Firmicutes (56.6%) and Bacteroidetes (33.1%), while the artificial consortium showed a significantly higher proportion of Firmicutes (85.5%) and a lower proportion of Bacteroidetes (4.6%). At species or genus level, Butyrivibrio fibrisolvens, the U2 group, Ruminococcus albus and Lachnospiraceae incertae sedis made up a higher proportion in the artificial consortium. The most dominant bacterial group was the Butyrivibrio-Pseudobutyrivibrio-Lachnospiraceae incertae sedis group, which accounted for 19.7% in the natural and 29.5% in the artificial consortium. Within the genus Butyrivibrio, the phylogenetic groups SA and VA2 and phylogeny-undefined Butyribivrio, but not VA1, were detected at high frequency in the artificial consortium. These results suggest that ecological and possibly functional relationships exist in the rumen among F. succinogenes, a subset of B. fibrisolvens, the U2 group, R. albus and Lachnospiraceae incertae sedis.

Distribution and diversity of members of the bacterial phylum Fibrobacteres in environments where cellulose degradation occurs.

The Fibrobacteres phylum contains two described species, Fibrobacter succinogenes and Fibrobacter intestinalis, both of which are prolific degraders of cellulosic plant biomass in the herbivore gut. However, recent 16S rRNA gene sequencing studies have identified novel Fibrobacteres in landfill sites, freshwater lakes and the termite hindgut, suggesting that members of the Fibrobacteres occupy a broader ecological range than previously appreciated. In this study, the ecology and diversity of Fibrobacteres was evaluated in 64 samples from contrasting environments where cellulose degradation occurred. Fibrobacters were detected in 23 of the 64 samples using Fibrobacter genus-specific 16S rRNA gene PCR, which provided their first targeted detection in marine and estuarine sediments, cryoconite from Arctic glaciers, as well as a broader range of environmental samples. To determine the phylogenetic diversity of the Fibrobacteres phylum, Fibrobacter-specific 16S rRNA gene clone libraries derived from 17 samples were sequenced (384 clones) and compared with all available Fibrobacteres sequences in the Ribosomal Database Project repository. Phylogenetic analysis revealed 63 lineages of Fibrobacteres (95% OTUs), with many representing as yet unclassified species. Of these, 24 OTUs were exclusively comprised of fibrobacters derived from environmental (non-gut) samples, 17 were exclusive to the mammalian gut, 15 to the termite hindgut, and 7 comprised both environmental and mammalian strains, thus establishing Fibrobacter spp. as indigenous members of microbial communities beyond the gut ecosystem. The data highlighted significant taxonomic and ecological diversity within the Fibrobacteres, a phylum circumscribed by potent cellulolytic activity, suggesting considerable functional importance in the conversion of lignocellulosic biomass in the biosphere.

Integrated 'omics analysis for studying the microbial community response to a pH perturbation of a cellulose-degrading bioreactor culture.

Integrated 'omics have been used on pure cultures and co-cultures, yet they have not been applied to complex microbial communities to examine questions of perturbation response. In this study, we used integrated 'omics to measure the perturbation response of a cellulose-degrading bioreactor community fed with microcrystalline cellulose (Avicel). We predicted that a pH decrease by addition of a pulse of acid would reduce microbial community diversity and temporarily reduce reactor function in terms of cellulose degradation. However, 16S rDNA gene pyrosequencing results revealed increased alpha diversity in the microbial community after the perturbation, and a persistence of the dominant community members over the duration of the experiment. Proteomics results showed a decrease in activity of proteins associated with Fibrobacter succinogenes 2 days after the perturbation followed by increased protein abundances 6 days after the perturbation. The decrease in cellulolytic activity suggested by the proteomics was confirmed by the accumulation of Avicel in the reactor. Metabolomics showed a pattern similar to that of the proteome, with amino acid production decreasing 2 days after the perturbation and increasing after 6 days. This study demonstrated that community 'omics data provide valuable information about the interactions and function of anaerobic cellulolytic community members after a perturbation.

A phylogenetic analysis of the phylum Fibrobacteres.

Members of the phylum Fibrobacteres are highly efficient cellulolytic bacteria, best known for their role in rumen function and as potential sources of novel enzymes for bioenergy applications. Despite being key members of ruminants and other digestive microbial communities, our knowledge of this phylum remains incomplete, as much of our understanding is focused on two recognized species, Fibrobacter succinogenes and F. intestinalis. As a result, we lack insights regarding the environmental niche, host range, and phylogenetic organization of this phylum. Here, we analyzed over 1000 16S rRNA Fibrobacteres sequences available from public databases to establish a phylogenetic framework for this phylum. We identify both species- and genus-level clades that are suggestive of previously unknown taxonomic relationships between Fibrobacteres in addition to their putative lifestyles as host-associated or free-living. Our results shed light on this poorly understood phylum and will be useful for elucidating the function, distribution, and diversity of these bacteria in their niches.

Isolation of a cellulolytic rod and its potential application in bio-ethanol production / Isolamento de bastão celulítico e sua potencial aplicação na produção de bio-etanol

With the world's focus on bio-fuel, cellulolytic microorganisms are being exclusively explored. In this paper, a strain of rod, NBG, was obtained from the rumen of Inner Mongolia sheep by an enrichment method with Whatman No.1 filter paper as the selective substrate. The strain was found to effectively degrade filter paper in solution. It was identified as Fibrobacter succinogenes based on DNA G + C mol %, together with morphological, physiological and biochemical tests. The endo-glucanase, -glucosidase and filter paper enzyme activity of NBG reached 62.5 ± 3.0 U•mL-1, 169.0 ± 9.4 U•mL-1 and 30.8 ± 5.4 U•mL-1, respectively, within 72 h of fermentation.

Com o foco mundial em biocombustíveis, microrganismos celuloliticos estão sendo exclusivamente explorados. Neste trabalho, uma cepa de bastão, NBG foi obtida do rumen de ovelhas do interior DA Mongolia com o método de enriquecimento e o papel de filtro No.1 como substrato seletivo. A cepa foi encontrada para degradar efetivamente o papel de filtro na solução. Foi identificado como Fibrobacter succinogenes baseado em DNA + c mol% juntamente com testes morofológicos, fisiológico e bioquímicos. A endo-glucanase e o papel de filtro chegaram com relação a atividade de enzima NBG 62.5 ± 3.0 U.ml-1, 169±9.4U.ml-1 e 30.8±5.4U.ml-1, respectivamente, com 72 horas de fermentação.