Biochemical Studies and Production Optimization of β-Glucosidase From Microcystis aeruginosa CACIAM 03 Using Organic Waste.

Global warming and industrial pollutants pose significant threats to environmental sustainability. In response, enzymes have emerged as promising tools for mitigating pollution. Enzymatic hydrolysis is considered environmentally sustainable due to its biological nature. In Brazil, the estimated agro-industrial waste production is an abundant source of lignocellulosic biomass, which contains cellulose, hemicellulose, and lignin. Its effective degradation requires a synergistic cocktail of enzymes, including cellulases, hemicellulases, and lignin-degrading enzymes. Within this system, β-glucosidases play a key role as a limiting factor in cellulose conversion, acting synergistically with other enzymes but being inhibited by glucose. This study aimed to produce and characterize β-glucosidases from the crude extract of the cyanobacterium Microcystis aeruginosa CACIAM 03. Enzyme production occurred after 10 days of incubation. The crude enzymatic extract exhibited optimal activity at pH 4.5 and 40°C (28.51 U/mL), high thermostability at 50°C (60% activity retained after 480 min), and tolerance to methanol (∼15% loss). The presence of Zn2+, Cl2+, and Mn2+ increased enzymatic activity by 2-3×. Using 300 µg of total protein from the crude enzymatic extract, the enzyme demonstrated high affinity for cellobiose, with K M app of 0.156 ± 0.02 mM and V ma x app of 0.246 ± 0.01 µM/min. These results reinforce the promising enzymatic potential of M. aeruginosa strains isolated from the Amazon region for sustainable biotechnological applications.