Production and characterization of a thermostable β-glucosidase from Myceliophthora heterothallica

Abstract

The conversion of biomass from agro-industrial residues into bioproducts is of great interest, especially to Brazil, where bioenergy has a huge potential for development. Enzymes involved in biodegradation of lignocellulosic biomass are those of the cellulase system, of which β-glucosidase is a constituent. The production and characterization of β-glucosidase by the thermophilic fungus Myceliophthora heterothallica by solid-state cultivation on different agro-industrial residues (sugarcane bagasse, sugarcane straw, wheat bran and a mixture of these three materials (1:1:1 w/w) was evaluated. Solid-state cultivation were conducted in 250 mL Erlenmeyer flasks, with 5 g of each substrate. Different culture parameters, such as supplementary nutrient solution to the substrate, supplementary nutrient solution pH, initial substrate moisture and fungus incubation temperature, were evaluated to establish conditions of higher enzyme production by the fungus The greatest production of enzymes occurred in a mixture of wheat bran, sugarcane bagasse and straw bagasse (1:1:1). The activity of β-glucosidase was greater under the following conditions: nutrient solution composed of NH4NO3, MgSO4.7H2O and (NH4)2SO4 (0.1%), at pH 4.5 or 6.0, fungus incubation at 40°C or 45°C, initial moisture of substrate at 80%. Enzyme presented optimum pH at pH 5.0 and good pH stability. Best temperature was 65°C and enzyme showed 100% stability for 1h, up to 60°C. The use of agro-industrial residues provided good production of β-glucosidase by fungus, with enzyme having the characteristics desirable from the industrial application.

Remote Sensing of Droplet Number Concentration in Warm Clouds: A Review of the Current State of Knowledge and Perspectives

“…Future opportunities for space‐based multiangle polarimetry for cloud retrievals include the 3MI instruments on ESA's METOP series that are based on POLDER (Marbach et al, ), as well as instruments on the Ukrainian Aerosol‐UA satellite (Milinevsky et al, ). Furthermore, the Hyper Angular Rainbow Polarimeter (HARP) is a cube sat mission due to be launched in 2018 that will provide data for selected targets during its 3‐month lifetime (Martins, ). In addition, a version of HARP is planned to be on the NASA Plankton, Aerosol, Clouds, Ocean Ecosystem (PACE) mission to be launched after 2022.…”