Process Biochemistry, Vol.75, 68-73, 2018
Broth recycling in high carbon demanding single cell oil fermentation increased the product to effluent generation ratio
In the attempt to minimize the incessant rise in industrial effluent discharge and maximize the existing resource utilization, present work demonstrates a proof of concept study on recycling of Single cell oil (SCO) fermentation effluent. To offset the high production cost associated with SCO fermentation, saccharified rice straw was utilized as cheap fermentable carbon (C) source. Fermentation broth formulated from Non-detoxified Liquid hydrolysate (NDLH) of rice straw(C: 50 g/l), was recycled without any dilution and carbon supplementation (mimicking a fermentation effluent) for two subsequent rounds to culture indigenous oleaginous yeast isolates NBT-8 and NBT-13. The resultant lipid titers in three consecutive fermentations were 1.036 g/l, 0.546 g/l, and 0.34 g/l from NBT-13 while 1.2 g/l, 0.96 g/l and 0.57 g/l from NBT-8 respectively. It was noteworthy that even at 100% recycle ratio, the NDLH based broth served as effective inexpensive substrate for NBT-8 up to two subsequent cycles resulting in good cumulative lipid titer of 2.16 g/l.