BIOMASS PRODUCTION OF Trichosporon sp.: FERMENTATION IN CASSAVA STARCH (MANIPUEIRA) USING DIFFERENT NITROGEN SOURCES

Abstract

Large amounts of cassava are processed both to obtain flour or starch, for human consumption or for industrial ends. Such process generates several wastes, solid or liquid, with peculiar characteristics, due to their starch and cyanogenic compounds. In order to contribute with some knowledge concerning to decrease the environmental impact or/and to utilize them as raw material, many scientist have been working on the subject. In this rework, microbial biomass production of Trichosporon sp using manipueira, the main liquid residue, as culture medium, has been studied especially to observe the influence of nitrogen supplementation. It was found that supplementation with ammonium sulfate allows to increase the biomass production up to 22.00 g/L, representing an increase of 138%, as compared with the control; indeed, this nitrogen source had better results if compared to urea. Carbon: nitrogen ratio of 5.15 was found to be the most interesting both to increase the biomass production and to reduce the residual sugar. With more nitrogen in the fermentation medium, the biomass showed more protein, and the order of correlation was significantly higher. Thermal treatment of manipueira shows a peculiar behavior considering that to produce high quality microbial biomass it is necessary to sterilize the medium and if the objective is to decrease the sugar content, the thermal treatment is no longer necessary.