Alpha-Ketoglutaric Acid Production from a Mixture of Glycerol and Rapeseed Oil by Yarrowia lipolytica Using Different Substrate Feeding Strategies

Waldemar Rymowicz,Magdalena Rakicka-Pustułka,Anita Rywińska,Piotr Juszczyk,Ludwika Tomaszewska-Hetman

doi:10.3390/su12156109

Waldemar Rymowicz, Magdalena Rakicka-Pustułka + Show 3 more

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https://doi.org/10.3390/su12156109

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Abstract

The microbiological biosynthesis of α-ketoglutaric acid (KGA) has recently captured the attention of many scientists as an alternative to its common chemical synthesis. The present study aimed to evaluate the effect of the feeding strategy of substrates, i.e., glycerol (G = 20 g·dm−3) and rapeseed oil (O = 20 g·dm−3), on yeast growth and the parameters of KGA biosynthesis by a wild strain Yarrowia lipolytica A-8 in fed-batch and repeated-batch cultures. The effectiveness of KGA biosynthesis was demonstrated to depend on thiamine concentration and the substrate feeding method. In the fed-batch culture incubated with 3 µg·dm−3 of thiamine and a substrate feeding variant 2G(_OGO), KGA was produced in the amount of 62.1 g·dm−3 at the volumetric production rate of 0.37 g·dm−3·h−1. These values of KGA production parameters were higher than these obtained in the control culture (with rapeseed oil only). During 10 cycles of the 1788-h repeated-batch culture carried out acc. to the feeding strategy 2G(_OGO), in the last 5 cycles the yeast produced from 55.6 to 58.2 g·dm−3 of KGA and maximally 2.9 g·dm−3 of the pyruvic acid as a by-product.

Highlights

Introduction αKetoglutaric acid (KGA), referred to as 2-ketoglutaric acid or oxoglutaric acid, is a dicarboxylic acid, endogenous in a human body
The first stage of our experiment was aimed at comparing the growth, glycerol consumption kinetics, and production of KGA and pyruvic acid (PA) in fed-batch cultures incubated with a thiamine, i.e., vitamin B1, concentration of 0.6 μg· dm−3, and with single substrates used as carbon sources in batches (Figure 1)
The production parameters of KGA by Y. lipolytica yeast are higher with the use of oil than with glycerol as a carbon source, it is very difficult to conduct long-term cultivation processes using hydrophobic substrates

Summary

Introduction

Ketoglutaric acid (KGA), referred to as 2-ketoglutaric acid or oxoglutaric acid, is a dicarboxylic acid, endogenous in a human body It is a key molecule in the effective protein metabolism. KGA affects the endocrine system because it its converted to glutamate and to arginine and ornithine, both of which stimulate the secretion of a growth hormone and an insulin-like growth factor 1 (IGF-1) [10]. It improves the absorption of Fe2+ ions in anemic patients [11], while athletes use it to improve the blood flow to muscles, reduce catabolism, and enhance protein synthesis [12]. KGA has been shown to retard aging processes in Caenorhabditis elegans cells [13]

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