Microbial degradation of cellulose wastes in continuous bioreactors

This paper reports on experiments concerning the biodegradation of cellulose wastes from wine-producing industries, as well as from cereal crops processing in agricultural farms, using cellulolytic bacterial and fungal species immobilized on radiopolymerized hydrogels. There are described three types of such bioreactors and their main features. The immobilization procedures have been achieved using the following species of microorganisms: Bacillus subtilis and B. licheniformis, from bacteria, as well as Pleurotus ostreatus and Trichoderma viride, from filamentous fungi. The immobilization matrices were prepared by radiopolymerization, using a 60Co radioactive source, designed for gamma irradiation. A consistent increasing of dry weight loss correlated with a correspondent enhancement of biodegradation rate by 10 - 20%, have revealed significant differences of metabolic activities between these immobilized bacteria and fungi on radiopolymerized hydrogels and those free cells cultures of the same microorganisms, which were grown on agar-agar gels and used as control references, in all performed experiments. Regarding the enzymatic activity of immobilized microorganisms the registered results have revealed an increasing of total reducing sugars with 20 - 30 mg g(-1). The enhancement of cellulolytic activity was higher with 0.1 - 0.3 U min(-1), in comparison with those values determined for the same process performed by the same microorganisms, used as control.