Identification of New Microbial Isolates Capable of Transforming Oleic Acid to Solely 10‐Hydroxystearic Acid

Abstract

Hydroxy fatty acids have a wide range of industrial applications including production of lubricants, plastics, waxes, cosmetics, and antimicrobial agents. Many plant oils contain a small amount of hydroxy fatty acids but are rich in oleic acid (OA) and linoleic acids. These fatty acids can be converted to hydroxy fatty acids by microorganisms with low to moderate yields. In some cases, OA can be converted to a mixture of 10-hydroxystearic acid (10-HSA) and 10-ketostearic acid (10-KSA). Oleate hydratase and secondary alcohol dehydrogenase (2o-ADH) are responsible for converting OA to 10-HSA and then 10-KSA, respectively. We are interested in obtaining microorganisms that can convert OA to solely 10-HSA without 10-KSA to eliminate downstream separation and purification of 10-HSA. While using CRISPR/Cas9 genome editing technology to knockout the 2o-ADH gene of Nocardia cholesterolicum NRRL5767 to obtain mutants that convert OA solely to 10-HSA (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0230915), we also isolated three new microorganisms from soil of corn and soybean fields that convert OA solely to 10-HSA in high yield. Here we report isolation and identification of three new Isolates capable of transforming OA to solely 10-HSA. These microbial isolates were identified by Gram Stain and 16S rRNA gene sequencing. We have successfully amplified a ~1500 bp region in the 16S rRNA using 27F and 1492R primer pair from the genome of these isolates by PCR. The sequence of the entire fragment was determined on both strands by Sanger's Chain Termination method. The resulting nucleotide sequence was then used to search similar sequences in rRNA/ITS databases using nucleotide BLAST. We were able to identify the genus of these three microbes confidently.