| Summary: | In searching for simultaneous chitosan and ethanol producing
microorganisms, mixed cultures of fungi for making tempe (a fermented soy bean
food originally from Indonesia) or tempe starter was examined. The fungi were
isolated from two different mixed cultures of fungi grown in Hibiscus and
Tectona gandis leaves called as Usar and Laru. Thirty two isolates were obtained
and they were tentarively identified belong to genus Rhizopus, Mucor,
Rhizomucor, and Absidia. Each fungus was cultivated on glucose as the carbon
source. Chitosan was successfully extracted from the cell wall of all isolates with
the yield ranging between 0.44 to 0.79 g/g of alkali insoluble material (AIM). The
degree of deacetylation of all extracted chitosans varied greatly from 0.96 to
61.3%. All isolates produced ethanol as the major metabolites with the maximum
yield varied between 0.26 and 0.41g ethanol/g glucose. Glycerol was the next
major metabolites, followed by lactic acid. Cultivation on agar plates containing
xylose, cellobiose, and cellulose showed that the highest growth rate was
observed on xylose followed by cellobiose and cellulose. Two isolates which were
identified as Rhizomucor were used for further investigation by cultivation on
liquid medium containing glucose, xylose and mixed sugar. The results showed
that sugar sources affect the yields of chitosan and ethanol as well as the degree of
deacetylation of the chitosan produced. Fourier Transform Infra Red Spectroscopy
analysis results showed that all chitosan extracted from the Isolates grown on
different sugar sources have similar spectrum with a commercial chitosan.
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