PRELIMINARY RESEARCH IN MICROORGANISM PRETREATMENT OF BIOMASS FOR LIGNOCELLULOSE DEGRADATION.

Obtaining bioethanol from lignocellulosic substrates is conditioned by degradation of vegetal substrates as much as possible. A fungal strain of Sporotrichumpulverulentumwas characterized morphologically and from enzyme production point of view in order to degrade corn stalks and wheat straw to obtain fermentable sugars. The production of hydrolytic enzymes (cellulases, amylases, proteases, lipases) was tested by qualitative analysis methods on specific culture media. The production of laccase, the enzyme involved in lignin degradation, was evaluated using guaiacol as substrate. The Sporotrichumpulverulentum strain was cultured on a rotary incubator at 150 rpm and 30 °C for 3 days to obtain the biomass used for inoculating the bioreactor. Substrate was physicochemically analysed for total solids (TS) and a dimensional analysis of substrate particles before and after fungal decompositionwas also performed. Corn stalks and respectively wheat straw were mixed with 3 L of water in a laboratory bioreactor type MINIFORS. The inoculation was carried out with 300 mL Sporotrichumpulverulentum culture obtained in the rotating incubator and the action of the fungal strain on corn stalks and wheat straw was followed for 3 days in the MINIFORS bioreactor at 30 °C, 200 rpm at a flow rate of 2 L·min-1. Samples were collected and substrate mass reduction, pH, sugar content by DNS method and dry matter were analysed. The results demonstrate that the pretreatmentwith the enzymes synthesized by Sporotrichumpulverulentum in liquid medium of lignocellulosic material resulted from agricultural activities can be further used, with excellent results, in obtaining bioethanol. [ABSTRACT FROM AUTHOR]