An Antarctic bacterial isolate displaying extracellular ${alpha}$-galactosidic activity was named Paenibacillus sp. LX-20 based on 16S rRNA gene sequence analysis. Optimal activity for the LX-20 ${alpha}$-galactosidase occurred at pH 6.0-6.5 and $45^{circ}C$. The enzyme immobilized on the smart polymer Eudragit L-100 retained 70% of its original activity after incubation for 30 min at $50^{circ}C$, while the free enzyme retained 58% of activity. The enzyme had relatively high specificity for ${alpha}$-D-galactosides such as p-nitrophenyl-${alpha}$-galactopyranoside, melibiose, raffinose and stachyose, and was resistant to some proteases such as trypsin, pancreatin and pronase. Enzyme activity was almost completely inhibited by $Ag^+$, $Hg^{2+}$, $Cu^{2+}$, and sodium dodecyl sulfate, but activity was not affected by ${eta}$-mercaptoethanol or EDTA. LX-20 ${alpha}$-galactosidase may be potentially useful as an additive for soybean processing in the feed industry.