ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Enhancing the production of gamma-linolenic acid in Hansenula polymorpha by fed-batch fermentation using response surface methodology
Bhimabol Khongto, Kobkul Laoteng, and Anan Tongta
Division of Biotechnology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Bangkhuntien, Bangkok, 10150 Thailand
Abstract: Gamma-linolenic acid (GLA, C18:3Δ6,9,12) is an n-6 polyunsaturated fatty acid (PUFA) that has been used for the alleviation and treatment of a number of symptoms and diseases.
Increasing GLA demand has led to a search for alternative producers and potential strategies for GLA production. Based on
the successful performance of Hansenula polymorpha, a methylotrophic yeast, as a “cell factory” for the production of valuable bioproducts, a bioprocess development approach
was implemented for GLA production in the recombinant yeast carrying the mutated Δ6-desaturase gene of Mucor rouxii. Using a substrate-feeding strategy under glycerol-limited conditions, the physical-chemical variables during the fed-batch
fermentation of the recombinant H. polymorpha were optimised for GLA production through response surface methodology using a Box-Behnken design. The medium composition,
including yeast extract and trace elements, and dissolved oxygen tension (DOT) were targeted. We found that DOT was the most
effective variable for enhancing GLA yield. These results also suggest that the optimum conditions for GLA production are
28 % saturation of DOT, 1 g L−1 of yeast extract and 3.6 mL L−1 of the Pichia trace metals 1 (PTM1).
Keywords: gamma-linolenic acid – Hansenula polymorpha – medium composition – dissolved oxygen tension – response surface methodology
Full paper is available at www.springerlink.com.
Chemical Papers 65 (2) 124–131 (2011)