Brevibacillus Thermoruber 9X-GLC, Bacteria Isolated from Hot Compost, Producer of a Beta-Glucosidase Resistant to Glucose Inhibition
Alejandro Sosa-Peinado , María Eugenia Hidalgo-Lara, Miguel Ángel Plascencia-Espinosa, Carla De la Cerna-Hernández, Sergio Rubén Trejo-Estrada and Edgar Arturo Téllez-Espino
American Journal of Biochemistry and Biotechnology
The thermotolerant strain Brevibacillus thermoruber 9X-GLC produces large amounts of β-D-glucosidase and cellobiohydrolase when grown on cellobiose and avicel. 9X-GLC was isolated from hot compost of sugarcane bagasse and filter mud and selected for its high enzymatic activity from a Bacilli collection of 77 isolates from soils and compost. Culture supernatants and ultrafiltered concentrates from shaken flask cultures of 9X-GLC were tested for their β-D-glucosidase activity and stability under different conditions of temperature, pH and glucose concentration. The concentrated supernatant from 9X-GLC cultures on cellobiose as sole carbon source had its highest β-D-glucosidase activity at 55°C; pH= 6.0 and retained 60% of its activity at a glucose concentration of up to 200 mM. The effect of different carbon sources on growth and β-D-glucosidase activity of concentrated supernatants was tested in 48 h shaken flask cultures of 9X-GLC. Glucose, cellodextrin and cellobiose supported high cell densities (>2×108 CFU/ml), whereas cellobiose and cellodextrin provided the best substrates for β-D-glucosidase production. The putative gene encoding β-D-glucosidase from 9X-GLC was obtained from PCR amplification and sequenced. The sequence of the putative structural gene of 2085 bp reveals 6 catalytic domains with high (>90%) homology to bacterialglycosidases.
© 2017 Alejandro Sosa-Peinado , María Eugenia Hidalgo-Lara, Miguel Ángel Plascencia-Espinosa, Carla De la Cerna-Hernández, Sergio Rubén Trejo-Estrada and Edgar Arturo Téllez-Espino. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.