Optimization of media and reaction conditions for production of polyol oils from soybean oil by Pseudomonas aeruginosa E03-12 NRRL B-59991

Authors: Hou, Ching; Ray, Karen

Submitted to: Biocatalysis and Agricultural Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2018
Publication Date: 10/13/2018
Citation: Hou, C.T., Ray, K.J. 2018. Optimization of media and reaction conditions for production of polyol oils from soybean oil by Pseudomonas aeruginosa E03-12 NRRL B-59991. Biocatalysis and Agricultural Biotechnology. 17:135-141. https://doi.org/10.1016/j.bcab.2018.10.006.
DOI: https://doi.org/10.1016/j.bcab.2018.10.006

Interpretive Summary: Soy-polyol oils (oxygenated triacylglycerols) are important starting materials for the manufacture of polymers such as polyurethane. Currently, they are produced by a chemical process involving several conversion steps. The objective of this study is to develop a new bioprocess to produce polyol oils directly from soybean oil. We first established a new method for microbial screening and products separation by using standard laboratory techniques. We then identified a microbial strain, Pseudomonas aeruginosa E03-12, that effectively converted soybean oil to polyol oils and optimized the growth medium and reaction conditions for production of this compound. These findings are important for developing scale up production of polyol oils directly from soybean oil and will benefit the U.S. farmers.

Technical Abstract: Soy-polyol oils (oxygenated acylglycerols) are important starting materials for the manufacture of polymers such as polyurethane. We reported methods for microbial screening and production of polyol oils from soybean oil through bioprocessing (Hou and Lin, 2013). Using this screening method, we screened 650 cultures isolated and found 50 cultures were positive for converting soybean oil to polyol oil. The two most active of these positive cultures are Acinetobacter haemolyticus A01-35 and Pseudomonas aeruginosa E03-12 (Hou et al 2015). The polyol oil produced by strain A01-35 was a mixture of hydroxy fatty acids-containing DAG. Strain E03-12 produced more polyol oil than strain A01-35 and its product contains both hydroxy fatty acids-containing DAG and TAG. We employed one-factor-at-a-time method to develop an optimized culture medium composition and reaction conditions for polyol oils production from soybean oil by strain E03-12. We found that among the different carbon sources studied, glucose at 12.5 g/L is the best. A combination of both tryptone at 12.5 g/L and yeast extract at 10 g/L serves as the best nitrogen source. Both iron and magnesium were studied for the effect of metal on the production of polyol oils. MgSO4 7H2O at 0.75 g/L and FeSO4 7H2O at 0.30 g/L produced the best result. Using this optimum medium composition, the best pH for the polyol oils production was found at 6.8. The optimum temperature for polyol oil production is 28 deg C. The optimum substrate concentration is 183 mg/30mL. In the time course studies with these optimum reaction conditions, the best yield is 18.5 mg/30mL at 48 hour. Longer incubation time leads to the decrease in product polyol oils and increase in DAGs due to the action of lipase. The information obtained from this study is important for developing scale up production of polyol oils directly from soybean oil.