Effects of Co-culture on Improved Productivity and Bioresource for Microalgal Biomass Using the Floc-Forming Bacteria Melaminivora Jejuensis
Donghyun Kim, Hyun-Sik Yun, Young-Saeng Kim, Jong-Guk Kim
Abstract
Bacterial and algal floc formation was induced by inoculating three species of wastewater-derived bacteria ( Melaminivora jejuensis, Comamonas flocculans , and Escherichia coli ) into algal cultures ( Chlorella sorokiniana ). Bacterial and algal flocs formed in algal cultures inoculated with M. jejuensis and C. flocculans , and these flocs showed higher sedimentation rates than pure algal culture. The floc formed by M. jejuensis (4988.46 ± 2589.81 μm) was 10-fold larger than the floc formed by C. flocculans (488.60 ± 226.22 μm), with a three-fold higher sedimentation rate ( M. jejuensis , 91.08 ± 2.32% and C. flocculans , 32.55 ± 6.33%). Biomass and lipid productivity were improved with M. jejuensis inoculation [biomass, 102.25 ± 0.35 mg/(L·day) and 57.80 ± 0.20 mg/(L·day)] compared with the productivity obtained under pure algal culture conditions [biomass, 78.00 ± 3.89 mg/(L·day) and lipids, 42.26 ± 2.11 mg/(L·day)]. Furthermore, the fatty acid composition of the biomass produced under pure algal culture conditions was mainly composed of C 16:0 (43.67%) and C 18:2 (45.99%), whereas the fatty acid composition of the biomass produced by M. jejuensis was mainly C 16:0 (31.80%), C 16:1 (24.45%), C 18:1 (20.23%), and C 18:2 (16.11%). These results suggest the possibility of developing an efficient method for harvesting microalgae using M. jejuensis and provide information on how to improve biomass productivity using floc-forming bacteria.