PubMed · 1000066
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
M Mandels. 1976. Saccharification technology.. https://pubmed.ncbi.nlm.nih.gov/1000066/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Cellulose is a renewable resource with broad biotechnological potential, and its hydrolysis by cellulases underpins applications such as biofuel production and biowaste valorization. This study combined isolation, screening, molecular identification, enzyme assays, genome sequencing, and bioreactor evaluation to characterize novel cellulase-producing bacteria. Preliminary screening identified and selected bacterial isolates by hydrolysis halo formation, with strains showing halos ≥ 20 mm selected for further quantitative assays. Streptomyces olivaceus C1_7A, Bacillus thuringiensis FBB7BB, and Bacillus licheniformis strains AT081C and AT082C showed the highest endoglucanase activities (from 0.11 to 0.26 U mL-1). Further testing on Arundo donax and Avicel led to the selection of B. thuringiensis FBB7BB and S. olivaceus C1_7A as the most promising strains for biotechnological application. Whole genome sequencing confirmed the presence of genes involved in polysaccharide degradation. Finally, lab-scale fermentation trials using 1-2% CMC showed that B. thuringiensis FBB7BB reached a maximum endo-1,4-β-glucanase activity of 0.30 ± 0.04 U mL-1 after 8 h at 37 °C, whereas S. olivaceus C1_7A achieved 0.36 ± 0.03 U mL-1 after 216 h at 30 °C.
Optimal culture conditions for obtaining low molecular mass endoglucanase (EG) from culture fluids of Trichoderma reesei were determined. The purification of this unglycosylated EG in a two-step procedure is described. In contrast to most cellulases, this EG did not bind to ConA-affinity columns. The unglycosylated fraction of the culture fluid proteins was further purified by preparative isoelectric focusing. Conditions relevant to an enzyme assay for this EG were determined (pH optimum 5.8, temperature optimum 52 degrees C).
Endoglucanase D from Clostridium thermocellum was purified from inclusion bodies formed upon its overproduction in Escherichia coli, using 5 M urea as a solubilizing solution. We examined the effects of denaturing agents upon the stability of the pure soluble enzyme as a function of the temperature. At room temperature, guanidinium chloride induces an irreversible denaturation. By comparison, we observed no structural or functional effects at room temperature using high concentrations of urea as denaturing agent. The irreversible denaturation process observed with guanidinium chloride also occurs with urea but only at elevated temperature (greater than or equal to 60 degrees C); in 6 M urea, the activation energy of the denaturation reaction is decreased by a factor of only 1.8. We interpret the high resistance of this protein to urea as reflecting a reduced flexibility of its structure at normal temperatures which should be correlated to the thermophilic origin of this protein.