Immobilization of Aspergillus terreus on loofa sponge for soyasapogenol B production from soybean saponin

Soyasapogenol B is known to have hepatoprotective, antimutagenic, antivirus, and anti-inflammatory activities. Among five porous carriers tested for immobilization of Aspergillus terreus II for soyasapogenol B production from soybean saponin, loofa sponge was the best immobilization carrier. Best yield of 83.64% soyasapogenol B was reached with six loofa disks loaded with 107 cells/mL spore concentration after 72 h in the first cycle. Effective soyasapogenol B yield was also observed using immobilized loofa disks in successive fermentations up to 8 batches and the highest yield (86.3%) was achieved on the third batch. Compared to free cell fermentation, soyasapogenol B productivity produced by immobilized loofa disks was 51.77% higher (64.2 mg/L h vs. 42.3 mg/L h), fermentation time was 33% lower (48 h vs. 72 h) and fermentation medium contents were reduced to half. Immobilization of A. terreus on loofa sponge, therefore, permits repeated reuse under the specified fermentation conditions for soyasapogenol B production.