title: 3-Hydroxypropionaldehyde-specific aldehyde dehydrogenase from Bacillus subtilis catalyzes 3-hydroxypropionic acid production in Klebsiella pneumoniae.
abstract: In Klebsiella pneumoniae, aldehyde dehydrogenases (ALDH) convert 3-hydroxypropionaldehyde (3-HPA) into 3-hydroxypropionic acid (3-HP). Although ALDHs can increase the production of 3-HP in K. pneumoniae, the substrate specificity of ALDH homologues from other microorganisms toward 3-HPA is less documented. Here we report that DhaS, a putative ALDH from Bacillus subtilis, shows high specificity toward 3-HPA when heterologously expressed in K. pneumoniae. Using NAD(+) as a cofactor, DhaS exhibited higher catalytic activity (2.3 U mg(-1)) and lower K m value (0.4 mmol l(-1)) toward 3-HPA than that toward other aldehydes. Under shake-flask conditions, the recombinant strain produced 2.1 g 3-HP l(-1) in 24 h, which is 3.9-fold of that in a control harboring a blank vector. Under non-optimized bioreactor conditions, the recombinant strain produced 18 g 3-HP l(-1) and 1,3-propanediol (1,3-PDO) at 27 g l(-1) in 24 h. The overall conversion rate from glycerol to 3-HP and 1,3-PDO reached 59.4 mol mol(-1). Homology modeling of DhaS illustrates substrate specificity and NAD(+)-binding site. DhaS is thus a 3-HPA-specific enzyme useful for production of 3-HP.
authors.affiliation: Beijing Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
authors.forename: Mingyue
authors.initials: M
authors.lastname: Su
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Xizhen
authors.initials: X
authors.lastname: Ge
authors.forename: Pingfang
authors.initials: P
authors.lastname: Tian
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology*; D001665:Binding Sites; D019149:Bioreactors / Q000382:microbiology; D001711:Biotransformation; D003001:Cloning, Molecular; D003067:Coenzymes / Q000378:metabolism; D015870:Gene Expression; D005985:Glyceraldehyde / Q000031:analogs & derivatives* / Q000378:metabolism; D007700:Kinetics; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D019344:Lactic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D011407:Propane / Q000378:metabolism*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D003067:Coenzymes; D011994:Recombinant Proteins; D009243:NAD; C047158:3-hydroxypropionaldehyde; D019344:Lactic Acid; D005985:Glyceraldehyde; C031601:hydracrylic acid; D000444:Aldehyde Dehydrogenase; D011407:Propane