Bioprospecção de actinomicetos com atividade lignocelulolítica para pré-tratamento da palha de cana-de-açúcar

Abstract

The present work aimed to reduce the cost of pre-treatment of lignin and cellulose present in lignocellulosic residues such as sugarcane straw, using bacterial inoculants of phylum actinomycetes, which help in the lysis of these residues turning them into simpler compounds, enabling the recycling of plant biomass. Actinomycetes were prospected through organic fertilizers and sugarcane straw. The cellulolytic enzymatic activity of the isolates was verified in vitro. The most efficient ones were selected to determine the activity of the enzymes lignin (through the laccase enzyme) and cellulose (through the DNS method) in sugarcane straw substrate. Morphological identification was also made by Gram and molecular staining using the ACTINO and 16S gene region. As a result good enzymatic activity was found in both isolates, identified as Gram-positive bacteria with 95% similarity with actinomycete and Gram-negative, with 96% similarity with Alcaligenes sp., which presents the need for a greater search for the functioning of their cellulolytic enzymes. For the cellulose enzyme test good degradation was verified for both, however a decrease was observed in the days after the production peaks, which may occur due to the enzymes being inhibited when the medium presents high glucose concentration or in non-sterile treatments. What may have occurred is the simultaneous consumption of the glucose produced. In the verification of lignolytic enzyme activity, the result was not significant. In conclusion, the use of bacterial inoculants isolated from biofertilizers has potential for biodegradation of lignocellulosic biomass.