Elucidating the salt-tolerant mechanism of Halomonas cupida J9 and unsterile ectoine production from lignocellulosic biomass

• Published in: Microbial cell factories 2024-08, Vol.23 (1), p.237-12, Article 237
• Main Authors: Chen, Yaping, Liu, Yujie, Meng, Yan, Jiang, Yuting, Xiong, Weini, Wang, Shufang, Yang, Chao, Liu, Ruihua
• Format: Article
• Language: English
• Subjects: Amino Acids, Diamino - biosynthesis; Amino Acids, Diamino - metabolism; Biomass; Control; Environmental aspects; Fermentation; Genetic aspects; Glucose - metabolism; Halomonas; Halomonas - genetics; Halomonas - metabolism; Halomonas cupida; Health aspects; Identification and classification; Lignin - metabolism; Lignocellulosic biomass; Methods; Promoter engineering; Salt stress (Botany); Salt Tolerance; Salt-tolerant mechanism; Unsterile ectoine production; Xylose - metabolism
• ISSN: 1475-2859; 1475-2859
• DOI: 10.1186/s12934-024-02515-w

Ectoine as an amino acid derivative is widely applied in many fields, such as the food industry, cosmetic manufacturing, biologics, and therapeutic agent. Large-scale production of ectoine is mainly restricted by the cost of fermentation substrates (e.g., carbon sources) and sterilization. In this study, Halomonas cupida J9 was shown to be capable of synthesizing ectoine using xylose as the sole carbon source. A pathway was proposed in H. cupida J9 that synergistically utilizes both WBG xylose metabolism and EMP glucose metabolism for the synthesis of ectoine. Transcriptome analysis indicated that expression of ectoine biosynthesis module was enhanced under salt stress. Ectoine production by H. cupida J9 was enhanced by improving the expression of ectoine biosynthesis module, increasing the intracellular supply of the precursor oxaloacetate, and utilizing urea as the nitrogen source. The constructed J9U-P8EC achieved a record ectoine production of 4.12 g/L after 60 h of xylose fermentation. Finally, unsterile production of ectoine by J9U-P8EC from either a glucose-xylose mixture or corn straw hydrolysate was demonstrated, with an output of 8.55 g/L and 1.30 g/L of ectoine, respectively. This study created a promising H. cupida J9-based cell factory for low-cost production of ectoine. Our results highlight the potential of J9U-P8EC to utilize lignocellulose-rich agriculture waste for open production of ectoine.