Research Article Open Access

Brevibacillus Thermoruber 9X-GLC, Bacteria Isolated from Hot Compost, Producer of a Beta-Glucosidase Resistant to Glucose Inhibition

Alejandro Sosa-Peinado1, María Eugenia Hidalgo-Lara2, Miguel Ángel Plascencia-Espinosa2, Carla De la Cerna-Hernández3, Sergio Rubén Trejo-Estrada4 and Edgar Arturo Téllez-Espino4
  • 1 Universidad Nacional Autónoma de México, Mexico
  • 2 Centro de Investigación y de Estudios Avanzados, Mexico
  • 3 Centro Universitario de Vinculación y Transferencia de Tecnología, Mexico
  • 4 Centro de Investigación en Biotecnología Aplicada del Instituto Politécnico Nacional, Mexico

Abstract

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.

American Journal of Biochemistry and Biotechnology
Volume 13 No. 4, 2017, 157-166

DOI: https://doi.org/10.3844/ajbbsp.2017.157.166

Submitted On: 13 December 2016 Published On: 20 October 2017

How to Cite: Sosa-Peinado, A., Hidalgo-Lara, M. E., Plascencia-Espinosa, M. &., Cerna-Hernández, C. D. L., Trejo-Estrada, S. R. & Téllez-Espino, E. A. (2017). Brevibacillus Thermoruber 9X-GLC, Bacteria Isolated from Hot Compost, Producer of a Beta-Glucosidase Resistant to Glucose Inhibition. American Journal of Biochemistry and Biotechnology, 13(4), 157-166. https://doi.org/10.3844/ajbbsp.2017.157.166

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Keywords

  • β-Glucosidase
  • Cellulose
  • Saccharification
  • Putative Sequence