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

Anaerobic cellulolytic microbes in gastrointestinal tract (GT) of ruminants have been well-documented, however, knowledge of aerobic microbes with cellulolytic activities in ruminant GT is comparably limited. Here, we unraveled aerobic cultivable cellulolytic microbes in GT of Ujimqin sheep (Ovis aries) and evaluated the cellulolytic potential of promising isolates. Twenty-two strains were found to possess cellulose degrading potential by Congo-red staining and phylogenetic analysis of the 16S rDNA/ITS sequence revealed that all strains belonged to nine genera, i.e., Bacillus, Streptomyces, Pseudomonas, Lactobacillus, Brachybacterium, Sanguibacter, Rhizobium, Fusarium, and Aspergillus. Strains with high cellulolytic activities were selected to further evaluate the various enzyme activities on lignocellulosic alfalfa hay (Medicago sativa). Among them, isolate Bacillus subtilis RE2510 showed the highest potential of cellulose degradation considering the high endoglucanase (0.1478 ± 0.0014 IU ml-1), exoglucanase (0.1735 ± 0.0012 IU ml-1) and β-glucosidase (0.3817 ± 0.0031 IU ml-1) after 10-day incubation with alfalfa hay. A significant destruction effect of the cellulose structure and the attachment of B. subtilis RE2510 to the hay were also revealed by using scanning electron microscope. This study expands our knowledge of aerobic cellulolytic isolates from GT of sheep and also highlights their potential application as microbial additive in the aerobic process of cellulose bioconversion.

Physicochemical Variation of the Main Components during Wild Pretreatment Process Based on the Concept of the Whole Utilization of Bamboo

Attempting to correlate the characteristics of the fractionated components from bamboo to its susceptibility to enzyme is often inconclusive depending on the parameters of pretreatment conditions. Based on the integrated analysis of chemical components, cellulose bioconversion, characteristic property of isolated hemicellulose, and lignin, the optimal mild pretreatment operation for Moso bamboo was 4% NaOH in 20% ethanol aqueous solution. A total of 91.9% mass was successfully recovered, and 66% bioconversion efficiency of the cellulosic sample was finally achieved. Meanwhile, over 25% hemicelluloses and 7% lignin were isolated, and the characteristic analysis indicated that the fractionated biomacromolecule maintained the original core structure, which is a benefit to be further utilized for the production of chemicals or polymers.

Bioethanol Production of Cellulase Producing Bacteria from Soils of Agrowaste Field

With decades of studies on cellulose bioconversion, cellulases have been playing an important role in producing fermentable sugars from lignocellulosic biomass. Copious microorganisms that are able to degrade cellulose have been isolated and identified. The present study has been undertaken to isolate and screen the cellulase producing bacteria from soils of agrowaste field. Cellulase production has been qualitatively analyzed in carboxy methylcellulose (CMC) agar medium after congo red staining and NaCl treatment by interpretation with zones around the potent colonies. Out of the seven isolates, only two showed cellulase production. The morphogical and molecular characterization revealed its identity as Escherichia coli and Staphylococcus aureus. The potential of organisms for bioethanol production has been investigated using two substrates, namely, paper and leaves by subjecting with a pre-treatment process using acid hydrolysis to remove lignin which acts as physical barrier to cellulolytic enzymes. Ethanolic fermentation was done using Saccharomyces cerevisiae for 24-48 h and then the bioethanol produced was qualitatively proved by iodoform assay. These finding proves that ethanol can be made from the agricultural waste and the process is recommended as a means of generating wealth from waste.

Cellulases of basidiomycetes for the development of cellulose bioconversion technologies

Basidiomycetes cultures were screened for the ability to actively express the cellulases complex. Nutrient media with various forms of sugars were used. From 22 cultures of macromycetes (14 species), a group of six cultures with high level activities of extracellular (Il-11 I. lacteus – 70 IU, Fvv F. velutipes – 78 IU, Pe-1 P. eryngii – 87 IU, Ps-1 L. sulphureus – 83 IU, Mg M. giganteus – 74 IU) and intracellular (Sc-51 S. commune – 102 IU) cellulase complex was selected. Cultures of the species exhibit notable differences in the expression of enzymes, which indicates a significant influence of genetic factors on the process of producer selection. Endo-1,4-β-D-glucanases isozymes for most fungi had a molecular weight of 55 kDa and above, except for S. commune, which had more variability of conformation and weight 12–55 kDa. The culture of Il-11 I. lacteus on media with Avicel and filter paper had the highest activity, its endo- and exo-1,4-β-D-glucanases activities ranged 37–39 IU/mL and 18–20 IU/ mL, respectively. The culture of S. commune Sc-51 is able to accumulate a significant amount of intracellular cellulases, but the production of culture fluid with high viscosity complicates technological manipulations and increases processing time. The obtained data allowed us to isolate an Il-11 I. lacteus culture with stable expression and high activity of the cellulases complex at different carbon sources.