Metabolic engineering for the production of copolyesters consisting of 3-hydroxybutyrate and 3-hydroxyhexanoate by Aeromonas hydrophila.
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 beta-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.
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
Yuan-Zheng
YZ
Qiu
Shao-Ping
SP
Ouyang
Zhongyao
Z
Shen
Qiong
Q
Wu
Guo-Qiang
GQ
Chen
D020155:3-Hydroxybutyric Acid / Q000737:chemistry / Q000378:metabolism*; D000102:Acetyl-CoA C-Acyltransferase / Q000235:genetics; D016980:Aeromonas hydrophila / Q000235:genetics* / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D002208:Caproates / Q000737:chemistry / Q000378:metabolism*; D020118:Cupriavidus necator / Q000201:enzymology / Q000235:genetics; D005818:Genetic Engineering; D006420:Hemeproteins / Q000235:genetics; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics; D000094122:Polyhydroxybutyrates
D020155:3-Hydroxybutyric Acid; D000102:Acetyl-CoA C-Acyltransferase; D000429:Alcohol Oxidoreductases; D001426:Bacterial Proteins; D002208:Caproates; D006420:Hemeproteins; D011091:Polyesters; D011994:Recombinant Proteins; C100771:Vgb protein, Bacteria; C115940:poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); D000094122:Polyhydroxybutyrates; C023744:acetoacetyl-CoA reductase