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Metabolic Engineering for the Production of Copolyesters Consisting of 3‐Hydroxybutyrate and 3‐Hydroxyhexanoate by Aeromonas hydrophila
Author(s) -
Qiu YuanZheng,
Ouyang ShaoPing,
Shen Zhongyao,
Wu Qiong,
Chen GuoQiang
Publication year - 2004
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200300090
Subject(s) - aeromonas hydrophila , metabolic engineering , recombinant dna , chemistry , fermentation , cofactor , biochemistry , bacteria , microbiology and biotechnology , gene , enzyme , biology , genetics
Summary: Aeromonas hydrophila 4AK4 was able to synthesize copolyesters consisting of 3‐hydroxybutyrate (3HB) and about 15 mol‐% 3‐hydroxyhexanoate (3HHx) (PHBHHx) when grown in long chain fatty acids such as dodecanoate regardless of growth conditions. To regulate the unit fraction in PHBHHx, phbA and phbB genes encoding β ‐ketothiolase and acetoacetyl‐CoA reductase in Ralstonia eutropha , were introduced into A. hydrophila 4AK4. When gluconate was used as cosubstrate of dodecanoate, the recombinant produced PHBHHx containing 3–12 mol‐% 3HHx, depending on the gluconate concentration in media. Vitreoscilla hemoglobin gene, vgb , was also introduced into the above recombinant, resulting in improved PHBHHx content from 38 to 48 wt.‐% in shake flask study. Fermentor studies also showed that increased gluconate concentration in medium containing dodecanoate promoted the recombinant strain harboring phbA and phbB genes to incorporate more 3HB unit into PHBHHx, resulting in reduced 3HHx fraction. Recombinant A. hydrophila harboring phbA , phbB and vgb genes demonstrated better PHBHHx productivity and higher conversion efficiency from dodecanoate to PHBHHx than those of the recombinant without vgb in fermentation study. Combined with the robust growth property and simple growth requirement, A. hydrophila 4AK4 appeared to be a useful organism for metabolic engineering.Metabolic pathways of PHBHHx biosynthesis in recombinant A. hydrophila 4AK4 (pTG01) from cosubstrates.