Shin Jonghyeok, Yu Jiwon, Park Myungseo, Kim Chakhee, Kim Hooyeon, Park Yunjeong, Ban Choongjin, Seydametova Emine, Song Young-Ha, Shin Chul-Soo, Chung Kyung-Hwun, Woo Ji-Min, Chung Hyunwoo, Park Jin-Byung, Kweon Dae-Hyuk
Department of Integrative Biotechnology, College of Biotechnology and Bioengineering , Sungkyunkwan University , Suwon 16419 , Republic of Korea.
Biomedical Institute for Convergence , Sungkyunkwan University , Suwon 16419 , Republic of Korea.
ACS Synth Biol. 2019 May 17;8(5):1055-1066. doi: 10.1021/acssynbio.8b00519. Epub 2019 May 7.
Whole cell biocatalysts can be used to convert fatty acids into various value-added products. However, fatty acid transport across cellular membranes into the cytosol of microbial cells limits substrate availability and impairs membrane integrity, which in turn decreases cell viability and bioconversion activity. Because these problems are associated with the mechanism of fatty acid transport through membranes, a whole-cell biocatalyst that can form caveolae-like structures was generated to promote substrate endocytosis. Caveolin-1 ( CAV1) expression in Escherichia coli increased both the fatty acid transport rate and intracellular fatty acid concentrations via endocytosis of the supplemented substrate. Furthermore, fatty-acid endocytosis alleviated substrate cytotoxicity in E. coli. These traits attributed to bacterial endocytosis resulted in dramatically elevated biotransformation efficiencies in fed-batch and cell-recycle reaction systems when caveolae-forming E. coli was used for the bioconversion of ricinoleic acid (12-hydroxyoctadec-9-enoic acid) to ( Z)-11-(heptanoyloxy) undec-9-enoic acid. We propose that CAV1-mediated endocytosing E. coli represents a versatile tool for the biotransformation of hydrophobic substrates.
全细胞生物催化剂可用于将脂肪酸转化为各种高附加值产品。然而，脂肪酸穿过细胞膜进入微生物细胞胞质溶胶的过程限制了底物的可用性，并损害了膜的完整性，进而降低了细胞活力和生物转化活性。由于这些问题与脂肪酸跨膜运输机制有关，因此构建了一种能够形成小窝样结构的全细胞生物催化剂，以促进底物内吞作用。大肠杆菌中窖蛋白-1（CAV1）的表达通过补充底物的内吞作用提高了脂肪酸运输速率和细胞内脂肪酸浓度。此外，脂肪酸内吞作用减轻了大肠杆菌中底物的细胞毒性。当使用形成小窝的大肠杆菌将蓖麻油酸（12-羟基十八碳-9-烯酸）生物转化为（Z）-11-（庚酰氧基）十一碳-9-烯酸时，这些归因于细菌内吞作用的特性在补料分批和细胞循环反应系统中显著提高了生物转化效率。我们认为，CAV1介导的内吞大肠杆菌是一种用于疏水底物生物转化的通用工具。
