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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Renewable Product Technology Research » Research » Publications at this Location » Publication #288238
Title: Screening of microbes for the production of polyol oils from soybean oil

Author
item Hou, Ching
item Lin, Jiann

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/13/2012
Publication Date: 12/13/2012
Citation: Hou, C.T., Lin, J.T. 2012. Screening of microbes for the production of polyol oils from soybean oil [abstract]. United States and Japan Cooperative Program in Natural Resources.

Interpretive Summary:

Technical Abstract: Introduction. More than 30.6 million tons of soybean oil were produced worldwide annually and the major use of this oil is for food products. Triacylglycerols (TAG) containing hydroxy fatty acids (FA), e.g., castor oil, have many industrial uses such as the manufacture of aviation lubricant, plastic, paint, nylons and cosmetics, because of the hydroxyl groups on the FA constituents. Castor oil is the only commercial source of TAG containing hydroxy FA. Diacylglycerols (DAG) containing hydroxy FA can also be used in the above mentioned industries. Soy-polyols (hydroxylated TAG) 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 then the subsequent opening of the oxirane ring. We have been working on finding new uses and new materials from soybean oil through bioprocesses. Our previous research established that microbial systems can convert FA to ricinoleic acid-type hydroxylated FA, including many bioactive FA such as monohydroxy-, dihydroxy- and trihydroxy-unsaturated FA, tetrahydrofuranyl unsaturated FA, and diepoxy bicyclic unsaturated FA. However, the biobased polymer industry requires acylglycerol (soybean oil) polyols and not FA polyols. The objective of this study is to develop a new bioprocess for the production of polyol oils directly from the substrate soybean oil. Bioconversion of soybean oil to polyol oils is a new research area without available methodology to follow. Here we report a new microbial screening and product separation method, as well as a bioprocess for the bioconversion of soybean oil directly to polyol oils. Materials and Methods. Microorganisms were isolated from soil and water samples collected from the vicinities of a biodiesel manufacturing plant in Ralston, IA, and from nearby Peoria, IL, U.S.A. TLC. TLC plates were developed with a two stage development procedure [5]: (i) benzene/ether/ethyl acetate/acetic acid (80:10:10:1 v/v) was developed with the solvent 8.5 cm above the origin; and (ii) hexane/ether/formic acid (80:20:2 v/v) developed in the same direction to the top of the TLC plate. The plate was air-dried before the second development. After development, products on the plate were identified first by exposure to iodine vapor and then by spraying with 60% aqueous sulfuric acid and charring. HPLC. HPLC were run on a Shimadzu model SCL-10A HPLC equipped with a SPD-M10A Diode Array Detector and a SIL-10AF Auto Injector (Colombia MO). HPLC method was modified from our previous reports [5,6]. A linear gradient starting with 100% methanol going to 100% 2-propanol over 60 min at 1 mL/min flow rate was used for our operation with a Supelco 25cm x 4.5 mm, 5 µ C18 reverse phase column. Detection was monitored at UV 205 nm. Electrospray ionization mass spectrometry (ESI-MS) and LC-MS were conducted as described in our previous paper. Results and discussion. For product separation, we found that TLC with a two step development solvent systems could separate the polyol products from substrate soybean oil. The products and substrates were separated in the following order: substrate triacylglycerols (Rf 0.8), free fatty acids (FA, Rf 0.7), product dihydroxy TAG (Rf 0.4), trihydroxy TAG (Rf 0.3), monohydroxy FA (Rf 0.1) and dihydroxy FA (Rf 0.05). We also found that our HPLC method was able to separate product polyol oils and substrate soybean oil. Free FA and Polyol oils (Diacylglycerols (DAG) containing hydroxyl FA) were eluted between 5 min to 15 min. DAG containing two normal FA was eluted between 15 min to 28 min and the substrate soybean oil was eluted between 36 min to 45 min. A total of 640 microbial cultures were screened and we identified 35 hits. As shown in figure 2, polyol oils were produced by one of our positive culture A01-35 and were separated nicely f