3-Hydroxypropionic acid (3-HP), a versatile and valuable platform chemical, has diverse industrial applications; but its biological production from glycerol is often limited by the capability of the enzyme aldehyde dehydrogenase (ALDH) to convert an intermediary compound, 3-hydroxypropionaldehyde (3-HPA), to 3-HP. In this study, we report a new ALDH, PuuC, from Klebsiella pneumoniae DSM 2026, that efficiently converts 3-HPA to 3-HP. The identified gene puuC was cloned, expressed in Escherichia coli, purified, and characterized for its properties. The recombinant enzyme with a molecular weight of 53.8 kDa exhibited broad substrate specificity for various aliphatic aldehydes, especially $C_2-C_5$ aldehydes. $NAD^+$ was the preferred coenzyme for the oxidation of most aliphatic and aromatic aldehydes tested. The optimum pH and temperature for PuuC activity were pH 8.0 and $45^{circ}C$. The $K_m$ values for 3-HPA and $NAD^+$ were 0.48 and 0.09 mM, respectively. The activity of PuuC was enhanced in the presence of reducing agents such as 2-mercaptoethanol or dithiothreitol, while several metal ions, particularly $Hg^{2+}$, $Ag^+$, and $Cu^{2+}$ inhibited its activity. The predicted=structure of PuuC indicated the presence of K191 and E194 in close proximity to the glycine motif, suggesting that PuuC belongs to class 2 ALDHs.