Production of enzymatic complex from agro-industrial biomass and its application in combustible ethanol

Adam Gonçalves Arruda,Vicelma Luiz Cardoso,Igor Vieira Evangelista,Larissa Soares De Menezes,Líbia Diniz Santos,Janaína Fischer,Carla Zanella Guidini

doi:10.33448/rsd-v10i6.13705

Adam Gonçalves Arruda, Vicelma Luiz Cardoso + Show 5 more

Open Access

https://doi.org/10.33448/rsd-v10i6.13705

Copy DOI

Abstract

Waste biomass and agro-industrial by-products, for production ethanol, will meet much of the great demand for this product. To reduce costs and optimize production, this study investigated solid-state fermentation (SSF) to obtain crude enzyme complex (CEC) from different agro-industrial biomasses (sugarcane bagasse, corn peel bran, rice straw bran and roasting and ground coffee residue) using cellulolytic fungi. The most promising CEC were evaluated in simultaneous hydrolysis and fermentation (SHF) for ethanol production by Saccharomyces cerevisiae in a culture broth containing sugarcane bagasse treated by steam explosion, and roast and ground coffee residue. In SSF with bioreactor volume of 0.25 L, containing 40 g of the biomass mixture and 40 g of sterile water with resuspended cells (1.0 x108 spores/g of solid medium) and temperature of 30±2 ºC, the strains Trichoderma reesei and Penicilium oxalicum provided the best enzyme activity. The CEC of T. reesei provided a concentration of 7.5 g L-1 of ethanol in a substrate containing treated sugarcane bagasse (60%) and roast and ground coffee residue (40%), under SHF conditions (pH 4.5, 35±2 °C, 48 h). The results obtained in this study show a promising alternative for correct disposal and use of residues and agro-industrial by-products by use in the production of enzymes and lignocellulosic ethanol.

Highlights

Lignocellulosic biomasses are renewable and sustainable raw materials used to produce bioethanol
The two strains were selected for the experiments.The observed higher performance corroborates with other researchers who report that species from the genera Trichoderma, Aspergillus, Penicillium, Chaetomium, Mucor and Clostridium, as well as other fungi, have the potential to produce enzymatic complexes used in the production of enzymes for hydrolysis of cellulosic biomass (Buzzini and Martini 2002; El-Said and Saleem 2008; Fischer et al, 2013; Rocha et al, 2013; Thomas et al, 2013; Althuri et al, 2017; Liu et al, 2020; Wang et al, 2020). 3.2 Selection of solid-state fermentation medium for crude enzyme complex (CEC) production The solid materials used as substrate for SSF were composed of widely available agro-industrial by-products
Medium 5 (40% SB, 30% CPB and 30% RGCR) enabled the production of an enzyme complex with greater enzyme activity for the two evaluated strains (6.1 and 5.4 FPU/mL for T. reesei and P. oxalicum, respectively)

Summary

Introduction

Lignocellulosic biomasses are renewable and sustainable raw materials used to produce bioethanol. Abundant in the form of residues from energy crops and agro-industrial products as well as food processing residues, they present themselves as an alternative to mitigate environmental impacts associated with energy demands, and uncertainties in relation to oil supply. Due to their recalcitrant structure, the steps for converting lignocellulosic materials are physical or thermochemical pretreatment, followed by some method to improve the accessibility and reactivity of carbohydrates, enzymatic hydrolysis for generation of fermentable sugars, and microbial fermentation to obtain fuel ethanol (Althuri et al, 2017; Li et al.; 2019; Robak and Balcerek, 2020). Enzymatic preparations in situ (Fischer et al, 2017; Lopes et al., 2017; Wang et al, 2020) and the simultaneous hydrolysis and fermentation processes represent a strategy to decrease operating costs, reduce inhibition and contamination, and facilitate recovery of the final product (Öhgren et al, 2007; Leduc et al, 2010; Gu et al, 2014; Guidini et al, 2014; Cuevas et al, 2015)

Methods

Results

Conclusion