Kinetics of alcoholic fermentation using guava (psidium guajava) seed flour and dry mycelium of aspergillus niger as nitrogen sources

Abstract

The kinetics of alcoholic fermentation was evaluated using the following substrates: molasses, urea, and diamine phosphate (MUDP); molasses and guava seed flour (MGSF); and molasses and dry mycelium of Aspergillus niger (MMAN). The fermentations were done using Saccharomyces cerevisiae under anaerobic conditions, 32°C, and pH 4.6. For each fermentation substrate the effect of the nitrogen source on cell viability (V), substrate conversion (CS), ethanol yield (Yp/s), and productivity was evaluated. The MGSF substrate showed the highest product yield (5.86 gg-1) and substrate conversion (47.58%) at 18 and 24 h of fermentation, respectively, with a maximum ethanol concentration of 60 gL-1. Substrate MMAN showed a low ethanol yield (36 gL-1). It was concluded that guava seed flour is a viable and economic nitrogen source for alcoholic fermentations.