Produção massal do fungo Clonostachys rosea em meio liquido

Abstract

Clonostachys rosea is a biocontrol agent for many plant pathogens, especially Botrytis cinerea. One of the limitations to market is its large-scale production, since it is performed in grains, which need a long incubation period, intense labor and large structures. Thus, this study evaluated the potential of liquid culture medium and environmental conditions that may interfere on the mass production of C. rosea conidia. All trials were performed in 250 mL Erlenmeyer, in agitation for seven days, and followed the experiment planning methodology for the reduction the number of trials and cost. After this phase, tests in bioreactor were conducted with the optimized medium. Initially, we studied the sources of carbon (sucrose and glucose/dextrose), as well as temperature, pH, photoperiod, carbon/nitrogen relation and water activity (glycerol). A screening was performed in which pH and photoperiod variables were considered significant for the conidia production. The optimization conditions were performed using a rotational central composite design (RCCD), with the extension of the range of pH and photoperiod values. The remaining variables were fixed according to the best resulting trial. Analyses of colony forming units (CFU), biomass and viability of the spores were performed. All trials were performed in triplicate and repeated four times. The carbon source that increased the conidia production in liquid medium was glucose/dextrose. The RCCD for the pH and photoperiod showed that the maximum conidia production predicted was of 1.78 x 107 conidia mL-1, 0.5576 g of dry biomass and 5.15 x 106 CFU mL-1 in the optimized conditions, with pH value of 4 and light for 12 h.