Bioetanol de segunda geração produzido a partir da biomassa de Eichhornia crassipes via hidrólise enzimática pelo fungo Grifola frondosa

Abstract

The biomass of Water Hyacinth (Eichhornia crassipes) shows promising potential for energy generation due to its renewable and abundant nature and its lignocellulosic chemical composition. Additionally, it serves as a phytoremediation plant for effluent treatment, allowing it to be cultivated in various environments without competing with the food industry, including sewage treatment plants. By utilizing this type of biomass, value is added to what was once considered waste, now regarded as an energy resource. This study aimed to compare the effects of chemical pretreatments with solutions of HCl and NaOH, both at a concentration of 0.5 mol·L⁻¹, and H₂O₂ at 3% (v/v) with pH adjusted to 11.5, in the proportions of 100 mL of solution per 5g of water hyacinth biomass. This was done through enzymatic hydrolysis performed by the fungus Grifola frondosa after 7, 14, 21, and 28 days of growth in a microbiological incubator at 25°C, and the fermentation process carried out with 10 mL of Escherichia coli bacteria previously cultured in liquid medium and 1g of commercial yeast Saccharomyces cerevisiae, both for each 100 mL of must. According to the methodologies used, it was found that chemical pretreatments had a positive influence on the biomass, as the best result obtained through this method was 77.6% with HCl after 7 days of hydrolysis and fermentation by the bacteria. In contrast, without chemical pretreatments and without the influence of hydrolysis, the highest alcohol content obtained was only 51.2% for leaves and stems fermented with E. coli, which already confers it potential application as a sanitizer. The density values were above the permissible limits, while the pH values ranged from 5.5 to 9.0, with most falling within the acceptable limits, as did the color and visual appearance, which met the requirements for all samples.