Study on several biological characteristics affected on the biofilm formation capacity of the phenol-degrading yeast Trichosporon asahii B1 isolated from Ha Long, Quang Ninh

Abstract

Several phenol-degrading and biofilm-forming yeast strains have been isolated from oil polluted sediment and water samples collected in Halong Bay, Quang Ninh. Amongst, QN-B1 strain with circle, convex, rough and white colony and 3-4 mm of diameter is considered as the best organism to degrade phenol and form biofilm. The yeast strains was then identified by ITS1-5.8rRNA-ITS2 sequencing analysis and showed homological coefficient of 99% with Trichosporon asahii. Based on morphological, bio-physical and bio-chemical characteristics, the strain was named as Trichosporon asahii QN-B1. It was signed in genbank as number KC139404. The influences of initial pH, NaCl concentrations and temperature on biofilm formation were investigated. As a result, the optimal biofilm formation conditions were pH from 3 to 7, NaCl of 1.5% and at 30^oC. It also could grow in the minimum mineral salt medium supplemented with 200ppm phenol. Using optimal condition of biofilm formation, the QN-B1 could degrade up to 90% of phenol with the initial concentration of 200 ppm. These results showed potential application of biofilm forming yeasts in treatment of phenol and other aromatic compounds polluted in water in Vietnam.