Characterization of Microalgae Growth-Promoting Bacteria (MGPB) isolated from Wastewater

摘要

Microalgae have recently attracted attention as a good alternative feedstock for biofuel production owing to their high growth rate and high liquids accumulation capabilities Microalgae biomass production has been demonstrated by using wastewater. Enhancing microalgae growth is critical to achieving a highly efficient microalgae biofuel production. We focused on microalgae growth-promoting bacteria (MGPB). However little is known about MGPB in wastewater. Therefore, the objectives of this study were to isolate and characterize MGPB from wastewater. We used 3 microalgae (Euglena gracilis, Chlamydomonas reinhardtii, and Chlorella vulgaris) as model microalgae and cultured them using wastewater. Seventy-three bacterial strains were isolated from the 3 microalgae (26 strains from E. gracilis, 29 strains from C. reinhardtii, and 18 strains from C. vulgaris). Almost all of isolated strains belonged to alpha-proteobacteria. We evaluated the effects of isolated strains on the growth of each host-microalgae species in sterile liquid medium and real wastewater sample. Some isolated strains significantly increase and accelerate host microalgae growth. Some isolated strain increase growth rate of microalgae up to 2 times or more. The results show that MGPB can be present in wastewaters and that the use of MGPB in microalgae culture can improve the efficiency of microalgae biofuel production.