Uso de modelos empíricos não-lineares para produzir a produção de celuloses utilizando Aspergillus niger e bagaço de cana de açúcar como substrato

Abstract

A variety of studies are being carried out with a view to producing fuels from renewable sources in order to diversify the energy matrix and minimize damage to the environment. Among them, second generation ethanol (2G) stands out, which is produced from non-food or lignocellulosic biomass, such as sugar cane bagasse, soybean meal, wheat bran, wood, bagasse fruit, corncob, among others. However, in the production of 2G ethanol high-cost enzymes are used to convert cellulose into fermentable sugars, making the process industrially unviable. An alternative to make the enzyme production process more competitive is to use agro-industrial waste as a carbon source for the microorganism. This work proposed the use of different concentrations of sugarcane bagasse as a carbon source for the production of cellulases from Aspergillus niger, in submerged fermentation with agitated tank bioreactor. And, later, empirical mathematical models were used to predict cellulose production, substrate consumption and cell growth. The maximum rate of variation of enzyme activity and substrate consumption were modeled with sigmoid equations, which feature the shape of an “S” curve. In the sequence, the maximum production of cells and the maximum consumption of oxygen in the reaction medium were determined, through the estimation of local extremes using empirical models known as Gaussian functions, which have a maximum (or minimum) point. For enzyme activity and substrate consumption, the MMF model was the one with the best fit. As for cell growth and oxygen consumption, the Extreme model showed better results