Produção de lipases por fermentação no estado sólido utilizando meios de baixo custo

Abstract

Lipases are biocatalysts applicable in various reactions, and thus attractive for industrial uses. Due to its biotechnological potential, the optimization of production processes has been studied. Currently, the production of these enzymes involves submerged fermentation (FS) and solid state fermentation (FES). When compared, FES has advantages such as the simplicity of the environment, as Brazil has an abundance of biomass and agro-industrial residues, simulation of the natural habitat of microorganisms and lower production cost. Its use results in products with added value, reducing costs and reducing environmental problems. The present work aims to study the production of lipases from Penicillium corylophilum by solid state fermentation (FES), using different culture media: sunflower seed meal (FSG), corn cake (TM) and cornmeal (T). To this end, the moistures of the culture media were determined in a moisture analyzer with an infrared lamp, the humidifying solution, water and phosphate buffer pH 7, 0.05 mol L-1 were studied, setting the final moisture at 55 % (v/m), the effect of lyophilization on the enzymatic activity of the fermented solid and an analysis of the costs for the production of P. corylophilum lipases by FES for the aforementioned media. The production of lipases was analyzed by lipolytic activity using the hydrolysis method of p-nitrophenyl palmitate (pNPP). For the medium with higher activity, the activity was also evaluated by the titrimetric method, using olive oil. The results showed that the amount of water to reach a moisture content of 55% varies for each substrate, being higher for T (3 mL of water/g of substrate) and lower for FSG (2.4 mL of water/g of substrate). Wheatear (T) had the highest lipolytic activity, 32.3 U g-1 S in 168 hours of culture. The measurement of lipolytic activity by the titrimetric method indicated the presence of “true” lipases and the activity was 97  11.9 U g-1 S. Regarding lyophilization, the residual activity was higher for FSG (83%) and very close for T (38%) and TM (40%). The cost analysis indicated very similar values for the three media, being the lowest for TM (BRL 73.99/100 g of dry substrate) followed by T (BRL 74.49/100 g of dry substrate) and FSG (BRL 75.41/100 g of dry substrate). Thus, analyzing the results of cost and activity losses during freeze-drying, wheat wheat would be more viable when one intends to use it without the need for freeze-drying, that is, application essentially in reactions where the aqueous medium is main, as showed the highest lipolytic activity and the second lowest value (R$ 74.49/100 g of dry substrate). However, for reactions where it is necessary to use a fermented product with low water contents, for example, in esterification reactions, FSG would be more viable, as the fermented solid showed less loss of activity after freeze-drying.