Produção de lacases utilizando resíduos e coprodutos agroindustriais

Abstract

Brazil stands out as one of the leading agricultural producers due to its vast territorial extension and high agricultural production. However, this enormous production also results in a considerable amount of waste. There is a growing trend towards the reuse of waste generated by agricultural activities, aiming for more sustainable processes. The production of enzymes from these wastes emerges as an option for an alternative destination, contributing to more sustainable practices. The cost associated with the production of enzymes, often high due to the use of complex media, can limit their application in several areas. In this context, the present study aimed to produce the enzyme laccase through submerged fermentation with the fungus Pleurotus ostreatus, using agro-industrial residues and co-products, such as soybean cake, sugarcane molasses, black liquor, and yeast extract. After selecting the variables that positively impacted laccase production, a 24-central rotational composite factorial design was developed, with triplicates at the central point. Quantification of laccase was carried out by the spectrophotometric method, using ABTS (2,2 azino-bis 3-ethylbenzothiazoline-6-sulfonic acid) as a substrate at 50 mM, at pH 3.0, at 50°C, for 5 minutes, and reading at 420 nm. The highest activity recorded was 16.9 U/mL, obtained at 5% soybean cake, 2.5% sugarcane molasses, 1% black liquor, and 7.5% yeast extract concentrations (m/ m). However, the negative influence of soybean cake and black liquor substrates on laccase production was highlighted. The quadratic model indicated the exclusion of black liquor and reduction of concentrations of soybean cake, sugarcane molasses, and yeast extract for subsequent experiments, aiming to increase the production of laccases.