Production of Bioactive Substances in Fed-batch and Semi-continuous Culture by Pleurotus Ostreatus

Therapeutic properties of Pleurotus genus are associated with the polysaccharides present in the mycelium cell wall and culture broth of submerged cultures. The production of extracellular polysaccharides (EPS) by Pleurotus ostreatus using fed-batch and semi-continuous culture with 50 and 75 % medium replacement was investigated. The assays were performed in 4L bioreactor with 40 g L-1 initial glucose concentration. Medium replacements were performed when residual glucose concentration reached 20 - 25 g L-1. The highest fungal biomass productivity was obtained in semi-continuous culture with 75 % medium replacement (61.02 mg L-1 h(-1)) followed by fed-batch (30.00 mg L-1 h(-1)) and 50 % medium replacement (23.4 mg L-1 h(-1)). However, the highest global EPS productivity (6.06 mg L-1 h(-1)) was obtained in semi-continuous culture with 50 % medium replacement. 75 % medium replacement and fed-batch led to EPS productivities of 4.03 and 3.78 mg L-1 h(-1), respectively. The highest EPS productivity was promoted by semi-continuous culture with 50 % medium replacement, in the second batch (9 mg L-1 h(-1)). This process can be improved in order to maintain this high productivity value in further batches. Fed-batch culture under tested conditions was not effective for EPS production by P. ostreatus.