关键词: 天冬氨酸族氨基酸, 微生物细胞工厂, 代谢工程, 合成生物学, 基因编辑

Abstract:

Amino acids are crucial components of animal feed, playing key roles in improving digestive function in livestock, enhancing meat quality, increasing protein conversion efficiency, and reducing reliance on soybean meal. Driven by global population growth and dietary changes, the rising demand for animal protein has strained the livestock industry. This industry traditionally depends heavily on soybean meal as its primary protein source, an approach that leads to low nitrogen utilization and exacerbates environmental pollution from nitrogen emissions. Aspartate-family amino acids, including L-lysine, L-methionine, L-threonine, and L-isoleucine, represent the most significant category of feed amino acids, accounting for nearly 90% of global consumption. They address current challenges by balancing feed nutrition according to the ideal protein standard and enabling a low-carbon transition in animal husbandry. The primary production method for these four amino acids is microbial fermentation, predominantly using Escherichia coli and Corynebacterium glutamicum as host organisms. Rapid advances in systems biology, synthetic biology, metabolic engineering, and evolutionary engineering have facilitated the construction and optimization of high-yield amino acid-producing strains. This has significantly enhanced production efficiency and substantially reduced costs. Based on an analysis of the aspartate-family amino acid biosynthetic pathways, this paper details strain modification methods and strategies. These encompass four key aspects: metabolic pathway reconstruction, metabolic pathway optimization, cofactor supply enhancement, and improved product efflux. These approaches have enabled the industrial-scale production of strains achieving high titers and yields. Finally, future research directions are discussed, focusing on three fronts: enhancing strain stress resistance in industrial environments, expanding the range of utilizable substrates, and optimizing dynamic regulatory systems. These advancements aim to provide theoretical guidance and technical support for developing high-performance amino acid-producing strains. The ultimate goal is to support the global transition towards efficient and environmentally sustainable feed amino acid production, thereby alleviating pressures on protein resources.

Key words: aspartate-family amino acids, microbial cell factory, metabolic engineering, synthetic biology, gene editing