Melanin synthesis using a new melanogenic strain of Flavobacterium kingsejongi and a recombinant strain of Escherichia coli expressing 4-hydroxyphenylpyruvate dioxygenase from F.kingsejongi

Author(s)
이한새
Alternative Author(s)
Han Sae Lee
Advisor
이평천
Department
일반대학원 분자과학기술학과
Publisher
The Graduate School, Ajou University
Publication Year
2022-02
Language
eng
Keyword
Melanins멜라닌
Alternative Abstract
Melanins are a heterologous group of biopolymeric pigments synthesized by diverse prokaryotes and eukaryotes and are widely utilized as bioactive materials and functional polymers in the biotechnology industry. Here, we report high-level melanin production using a new melanogenic Flavobacterium kingsejongi strain and a recombinant Escherichia coli overexpressing F. kingsejongi 4-hydroxyphenylpyruvate dioxygenase (HPPD). Melanin synthesis by the F. kingsejongi strain was confirmed via melanin synthesis inhibition tests, melanin solubility tests, genome analysis, and structural analysis of the purified melanin from both wild-type F. kingsejongi and recombinant E. coli expressing F. kingsejongi HPPD. The activity of F. kingsejongi HPPD was demonstrated via in vitro assays with 6×His-tagged and native forms of HPPD. Bioreactor fermentation of F. kingsejongi produced a large amount of melanin with a titer of 6.07 ± 0.32 g/L, a conversion yield of 60% (0.6 ± 0.03 g melanin per gram tyrosine), and a productivity of 0.03 g/L·h, indicating its potential for industrial melanin production. Additionally, bioreactor fermentation of recombinant E. coli expressing F. kingsejongi HPPD produced melanin at a titer of 3.76 ± 0.30 g/L, a conversion yield of 38% (0.38 ± 0.03 g melanin per gram tyrosine), and a productivity of 0.04 g/L·h. Both strains showed sufficiently high fermentation capability to indicate their potential as platform strains for large scale bacterial melanin production.
URI
https://dspace.ajou.ac.kr/handle/2018.oak/20730
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Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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