A lytic bacterium's potential application in biofuel production through directly lysing the diatom Phaeodactylum tricornutum cell

The isolation of microorganisms able to break the cell wall of algal species would contribute to the release of starch and lipid molecules for biofuel production. In this study, a special plaque-forming bacterium, forming plaques of about 2 cm in diameter, was found to target the diatom Phaeodactylum tricornutum. To monitor the dynamic effects of the bacterium on P. tricornutum, samples from both normal algal cultures and lysates were analyzed by fluorescence microscopy and denaturing gradient gel electrophoresis. The DGGE results showed that there was no different band between normal algal cultures and lysate samples, suggesting the bacterium's low abundance. Several different culture mediums were tried, and the obtained bacteria from the lysates were further investigated using the plaque-forming method. Finally, one isolated bacterium grown on culture medium containing P. tricornutum cells showed the special lytic activity. The results from sequence and phylogenetic analysis show that this bacterium belongs to the genus of Labrenzia in the family Rhodobacteraceae. This study demonstrates the isolation of a lytic bacterium that has a potential for biofuel production through P. tricornutum 'cracking'. (C) 2015 Elsevier B. V. All rights reserved.