Bioprospecting of yeasts for amylase production in solid state fermentation and evaluation of the catalytic properties of enzymatic extracts

Abstract

Profiling microorganisms with potential for amylase production in low cost culture media has been widely recognized due to its broad applicability. The aim of this study was to select yeast strains with potential to produce amylolytic enzymes by solid state fermentation. Fifty-four (54) strains were assessed and three exhibited ability to produce amylases: Candida parapsilosis with 14.68 U/mL (146.8 U/g substrate); Rhodotorula mucilaginosa with 25.0 U/mL (250 U/g substrate), and Candida glabrata with 25.39 U/mL (253.9 U/g substrate), in solid state fermentation, for 120 h at 28°C, using wheat bran with 70% moisture. The enzymes exhibited maximum activity at a pH of 7.0 and at 60°C. Amylases demonstrated satisfactory structural stability, maintaining their catalytic activity after 1 h at 50°C. All enzymes were ethanol tolerant and retained more than 70% of their original activities in 15% ethanol solution. Corn starch was efficiently hydrolyzed by enzymes and the extracts produced by C. parapsilosis and C. glabrata exhibited dextrinizing activity, while those produced by R. mucilaginosa exhibited saccharifying activity.

Production and Catalytic Properties of Amylases fromLichtheimia ramosaandThermoascus aurantiacusby Solid-State Fermentation

“…Ethanol inhibition is a strong trend in the study of certain enzymes, since they can be exposed to substantial concentrations of alcohol for various industrial applications [6]. The results demonstrate that amylase produced by L. ramosa showed residual activity around 65% and T. aurantiacus amylase showed greater than 90% residual activity when incubated at concentrations of 10% ethanol (Figure 3).…”

“…Hydrolysis of starch by enzymatic methods has advantages compared to that with chemical methods, such as operating under mild conditions of pH and temperature, preventing equipment corrosion, and subsequent neutralization steps. Enzymes have substrate specificity, eliminating the formation of undesirable by-products, commonly observed in acid hydrolysis [5, 6]. …”

“…In this regard, agroindustrial residues have been used as substrates for microbial-derived enzymes under solid-state fermentation (SSF) [10, 11] and several published works have used this process for the production of various enzymes [6, 12–14]. …”

Production of xylanase by a new strain of Thermoascus aurantiacus: obtainment of enzymatic extract with reduced cellulolytic activity for application in pulp and paper industries

“…The production of microbial enzymes by solid-state fermentation is directly related to the nutritional composition and accessibility of the substrate (BRIENZO et al, 2012;STROPARO et al, 2012). Wheat bran is a substrate with good water absorption capacity, and its composition favors microbial cultivation for enzymes production (OLIVEIRA et al, 2015). Previous studies have reported the production of cellulases and hemicellulases by solid-state fermentation in wheat bran by several microorganisms (RODRIGUEZ-ZUNIGA et al, 2011;DELABONA et al, 2012;MASUI, et al, 2012;MITTAL, et al, 2013;GOWDHAMAN et al, 2014;PIROTA et al, 2015).…”

“…The use of enzymes in industrial scale remains limited because of their high production costs (OLIVEIRA et al, 2015). An alternative for reducing the final cost of these biomolecules involves the use of agro-industrial residues in solidstate fermentation to produce microbial enzymes (BRIENZO et al, 2012;MASUI et al, 2012;SILVA et al, 2013;TERRASAN and CARMONA, 2015).…”