Bioconversion of Sweet Sorghum Residues by Trichoderma citrinoviride C1 Enzymes Cocktail for Effective Bioethanol Production

Abstract

Improved cost-effective bioethanol production using inexpensive enzymes preparation was investigated. Three types of waste lignocellulosic materials were converted—for the production of enzyme preparation, a mixture of sugar beet pulp and wheat bran, while the source of sugars in hydrolysates was sweet sorghum biomass. A novel enzyme cocktail of Trichoderma citrinoviride C1 is presented. The one-step ultrafiltration process of crude enzyme extract resulted in a threefold increase of cellulolytic and xylanolytic activities. The effectiveness of enzyme preparation, compared to Cellic® CTec2, was tested in an optimized enzymatic hydrolysis process. Depending on the test conditions, hydrolysates with different glucose concentrations were obtained—from 6.3 g L−1 to 14.6 g L−1 (representing from 90% to 79% of the CTec2 enzyme yield, respectively). Furthermore, ethanol production by Saccharomyces cerevisiae SIHA Active Yeast 6 strain DF 639 in optimal conditions reached about 120 mL kg d.m.−1 (75% compared with the CTec2 process). The achieved yields suggested that the produced enzyme cocktail C1 could be potentially used to reduce the cost of bioethanol production from sweet sorghum biomass.

Cost reduction approaches for fermentable sugar production from sugarcane bagasse and its impact on techno-economics and the environment

“…But in the present experiments restricting the duration of hydrolysis of 48h, fortunately, favoured the maximum sugar release at 52.5C. It should be noted that Kancelista et al (2020) have also reported optimal conditions for Cellic CTec2 being 52.7C and pH 5.2 using the Box Behnken model, which resulted in maximum ethanol yield during separate hydrolysis and fermentation of sweet sorghum.…”