Lakshmi Pillai and Anita Katkade
Abstract
Erythritol, a low-calorie polyol, is widely recognized for its applications as a sugar substitute in the food, pharmaceutical, and cosmetic industries. Microbial production of erythritol using Yarrowia lipolytica offers a sustainable and cost-effective alternative to chemical synthesis, particularly when utilizing crude glycerol, a byproduct of biodiesel production, as a substrate. However, the erythritol yields from wild-type strains are often suboptimal, necessitating strain improvement strategies. In this study, UV and NTG (N-methyl-Nâ-nitro-N-nitrosoguanidine) mutagenesis were employed to enhance erythritol production in Yarrowia lipolytica (MTCC 951). Two mutants, UV-M5 and NTG-M12, were selected for their significantly improved erythritol yields, achieving 81.4 g/l and 99.8 g/l, respectively, compared to 45.2 g/l in the wild-type strain. The mutants also demonstrated superior substrate utilization, with 92% and 95% of crude glycerol consumed, respectively, versus 78% in the wild-type. High-performance liquid chromatography (HPLC) confirmed the purity of the produced erythritol (>98%), while Fourier-transform infrared spectroscopy (FTIR) validated its chemical structure through characteristic peaks at 3340 cm-¹ (O-H stretching), 2940 cm-¹ (C-H stretching), and 1050 cm-¹ (C-O stretching). These results underscore the effectiveness of UV and NTG mutagenesis in enhancing erythritol production and substrate utilization in Yarrowia lipolytica. The study highlights the potential of crude glycerol as a sustainable substrate and provides a foundation for further optimization and scale-up of microbial erythritol production for industrial applications.