Whole-Cell Biotransformation of 1,12-Dodecanedioic Acid from Coconut Milk Factory Wastewater by Recombinant CYP52A17SS Expressing Saccharomyces cerevisiae

Phawadee Buathong,Gilles Truan,Nassapat Boonvitthya,Warawut Chulalaksananukul

doi:10.3390/pr8080969

Abstract

Biotransformation of fatty acids from renewable wastewater as feedstock to value-added chemicals is a fascinating commercial opportunity. α,ω-Dicarboxylic acids (DCAs) are building blocks in many industries, such as polymers, cosmetic intermediates, and pharmaceuticals, and can be obtained by chemical synthesis under extreme conditions. However, biological synthesis can replace the traditional chemical synthesis using cytochrome P450 enzymes to oxidize fatty acids to DCAs. Saccharomyces cerevisiae BY(2R)/pYeDP60-CYP52A17SS (BCM), a transgenic strain expressing the galactose-inducible CYP52A17SS cytochrome P450 enzyme, was able to grow in a coconut milk factory wastewater (CCW) medium and produced 12-hydroxydodecanoic acid (HDDA) and 1,12-dodecanedioic acid (DDA). The supplementation of CCW with 10 g/L yeast extract and 20 g/L peptone (YPCCW) markedly increased the yeast growth rate and the yields of 12-HDDA and 1,12-DDA, with the highest levels of approximately 60 and 38 µg/L, respectively, obtained at 30 °C and pH 5. The incubation temperature and medium pH strongly influenced the yeast growth and 1,12-DDA yield, with the highest 1,12-DDA formation at 30 °C and pH 5–5.5. Hence, the S. cerevisiae BCM strain can potentially be used for producing value-added products from CCW.

Highlights

Thailand is the world’s ninth largest producer of coconut, with the east and south coastal areas being used for the large-scale production of coconuts [1], which amounted to 856,920 tons in 2018 and is increasing annually
The Dicarboxylic acids (DCAs) (≥98%), 12-hydroxydodecanoic acid (HDDA) (97%), and 1,12-dodecanedioic acid (DDA) (99%), which were used as the standards for the gas chromatography (GC) analysis, were purchased from Sigma-Aldrich, St
The S. cerevisiae BCM and the control untransformed BY(2R) strains were grown in coconut milk processing wastewater (CCW) or YPCCW

Summary

Introduction

Thailand is the world’s ninth largest producer of coconut, with the east and south coastal areas being used for the large-scale production of coconuts [1], which amounted to 856,920 tons in 2018 and is increasing annually. Coconut milk extraction results in the production of the waste byproducts, which are comprised of solid fat and wastewater. 2000–3000 kg of coconut milk are lost every day into wastewater during the extraction process [2,3]. The coconut oil in the wastewater pond can be Processes 2020, 8, 969; doi:10.3390/pr8080969 www.mdpi.com/journal/processes. Processes 2020, 8, 969 changed into solid fat that floats to the top of the wastewater and can be eliminated from the wastewater pond and used as a substrate for biogas fermentation [4]. The residual coconut milk processing wastewater (CCW) can be a severe environmental and health problem, forming an odor and foul air in the neighborhood, clogging, and harboring pathogens [3,5,6]

Methods

Results

Conclusion