Identification and Saccharifying Activity of Wild Microbial Flora Used in the Manufacturing of Tiquira

Abstract

Tiquira is an alcoholic distillate handmade prepared from the simultaneous saccharification and fermentation of cassava. The saccharification and fermentation processes are carried out by wild microorganisms, randomly harvested, from the natural exposure of beijus to the environment. The growth of these microorganisms occurs for a period of 8 days, and starch hydrolysis and sugar fermentation are performed for the same period. As there are several strains collected, the quality of the distillate is compromised, resulting in defects in the composition of the drink and in the variable process yield. The objective of this work was to isolate, identify and select, among the native microorganisms, the best saccharifying and fermentative agents, enabling the production of inoculum to reduce the process time and to homogenize Tiquira's secondaries. Among the selected strains, it was possible to identify and characterize three species of filamentous fungi: Aspergillus niger, Aspergillus flavus and Rhizopus oryzae. For all of them, SDA (Saboroud Dextrose Agar) medium, at 30 °C, was the one that best allowed fungal growth. Regarding starch saccharification yield, R. oryzae achieved a conversion value of 78.0 % (30 °C, 5.5 x 107 spore content, pH 5 and 50 g/L soluble starch), whereas A. flavus, A. niger, and the mixture of all of them, had a conversion rate of 71.5; 57.2 and 48.0 %, respectively, which highlights that the use of autochthonous filamentous microorganisms is an option for the saccharification of starch samples.