Production of polyol oils from soybean oil by bioprocess: results of microbial screening and identification of positive cultures

Recently we reported methods for microbial screening and production of polyol oils from soybean oil through bioprocessing (Hou and Lin, 2013). Soy-polyol oils (oxygenated acylglycerols) are important starting materials for the manufacture of polymers such as polyurethane. Currently, they are produced by a two-step chemical process involving epoxidation and subsequent opening of the oxirane ring. A total of 650 cultures isolated from soil samples collected from a biodiesel plant in Iowa and from soil and water samples collected from Peoria, IL were screened for the production of polyol oil from soybean oil. Out of these 650 cultures screened, 50 cultures were positive for converting soybean oil to two product groups: diacylglycerol polyol oil (polyol DAGs) and diacylglycerol (DAD) with normal fatty acids. These two product groups can be separated by a two-solvent system TLC. In this study, we identified the 11 most active of these positive cultures using 16S rRNA gene analysis. The 11 strains investigated were found to be bacterial and no active yeast strains were found in the present study. Phylogenetic analysis identified two strains A01-35 and E03-25 as Acinetobacter haemolyticus, a single strain was identified as Pseudomonas aeruginosa, the other active strains were identified as Pseudomonas protegens.