AUTHOR=Park Jungsoo , Park Bum Soo , Wang Pengbin , Patidar Shailesh K. , Kim Jin Ho , Kim Sae-Hee , Han Myung-Soo 

TITLE=Phycospheric Native Bacteria Pelagibaca bermudensis and Stappia sp. Ameliorate Biomass Productivity of Tetraselmis striata (KCTC1432BP) in Co-cultivation System through Mutualistic Interaction

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00289

DOI=10.3389/fpls.2017.00289

ISSN=1664-462X

ABSTRACT=<p>Effective sustainable algal cultivation techniques are essential for mass production of the marine microalga <italic>Tetraselmis</italic> for biofuel and array of co-products. The phycospheric communities affect the microalgal growth and metabolism through various allelochemical and nutrient interactions; hence, their potential to affect the quantity and quality of both biomass and bioproducts is significant. In the present study, we have screened the phycospheric communities of biofuel producing <italic>Tetraselmis striata</italic> (KCTC1432BP). A total of 26 bacterial strains were isolated and identified from the phycosphere of <italic>T. striata</italic> mass culture. Then, each bacterial strain was tested in co-cultivation conditions with <italic>T. striata</italic> for evaluating its growth promoting and inhibitory effects. Among these all strains, two promising strains (<italic>Pelagibaca bermudensis</italic> KCTC 13073BP and <italic>Stappia</italic> sp. KCTC 13072BP) were selected because of their maximum growth promoting effects and mutualistic interactions. The growth rate, biomass productivity, lipid contents, and fatty acids were analyzed during their combined growth in O3 media and compared with axenic growth of <italic>T. striata</italic>. Later, growth promoting mechanisms in the co-cultivation environment were investigated for these promising bacterial strains under replete and limited conditions of nutrients (nitrate, phosphate, and vitamin B<sub>12</sub>). The growth promoting potential of <italic>P. bermudensis</italic> was illustrated by the two fold enhancement in biomass productivity. These bacteria are promising for microalgal cultivation without any negative effects on the native seawater bacterial communities, as revealed by next generation sequencing analysis. This study represents, to date, the first report highlighting the role of phycospheric growth promoting bacteria of promising biofuel feedstock <italic>T. striata</italic>.</p>