In:
Scientific Reports, Springer Science and Business Media LLC, Vol. 7, No. 1 ( 2017-12-07)
Abstract:
3-Hydroxypropionic acid (3-HP) can be produced via the biological route involving two enzymatic reactions: dehydration of glycerol to 3-hydroxypropanal (3-HPA) and then oxidation to 3-HP. However, commercial production of 3-HP using recombinant microorganisms has been hampered with several problems, some of which are associated with the toxicity of 3-HPA and the efficiency of NAD + regeneration. We engineered α-ketoglutaric semialdehyde dehydrogenase (KGSADH) from Azospirillum brasilense for the second reaction to address these issues. The residues in the binding sites for the substrates, 3-HPA and NAD + , were randomized, and the resulting libraries were screened for higher activity. Isolated KGSADH variants had significantly lower K m values for both the substrates. The enzymes also showed higher substrate specificities for aldehyde and NAD + , less inhibition by NADH, and greater resistance to inactivation by 3-HPA than the wild-type enzyme. A recombinant Pseudomonas denitrificans strain with one of the engineered KGSADH variants exhibited less accumulation of 3-HPA, decreased levels of inactivation of the enzymes, and higher cell growth than that with the wild-type KGSADH. The flask culture of the P. denitrificans strain with the mutant KGSADH resulted in about 40% increase of 3-HP titer (53 mM) compared with that using the wild-type enzyme (37 mM).
Type of Medium:
Online Resource
ISSN:
2045-2322
DOI:
10.1038/s41598-017-15400-x
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2017
detail.hit.zdb_id:
2615211-3
