Predicting the Production of Probiotic Biomass and Lactic Acid via Fuzzy Logic during the Anaerobic Treatment of Swine Waste (<i>Sus domestica</i>) with <i>Lactobacillus</i> <i>acidophilus</i>

Abstract

The massive generation of pig manure significantly contributes to the emission of greenhouse gases; in addition, its poor disposal represents a serious risk to human and animal health. In recent years, the microbial fermentation process has become relevant because it is considered a circular bioeconomy strategy, guaranteeing the recovery of agro-industrial waste and waste management. In this work, the production of lactic acid and biomass was evaluated from an anaerobic bioconversion process of swine residues in the presence of L. acidophilus. A 5&nbsp;L capacity reactor was used, and different stirring speeds were evaluated (100, 150, and 200&nbsp;rpm). It was concluded that the highest production of lactic acid and biomass was 30.15 and 111.52 g/L, respectively, which were reached during the experiments carried out at 100&nbsp;rpm. The biomass was analyzed to determine the content of carbohydrates, proteins, and cell count, which were 0 g/L, 17.16%, and 3.45×107cfu/g, respectively. Finally, the fuzzy logic technique was applied, and response surface graphs were generated to determine the variables with the greatest impact on lactic acid and biomass generation.