Bioresource Technology, Vol.278, 73-81, 2019
Novel thermostable enzymes from Geobacillus thermoglucosidasius W-2 for high-efficient nitroalkane removal under aerobic and anaerobic conditions
In this study, a thermophilic facultative anaerobic strain Geobacillus thermoglucosidasius W-2 was found to degrade nitroalkane under both aerobic and anaerobic conditions. Bioinformatical analysis revealed three putative nitroalkane-oxidizing enzymes (Gt-NOEs) genes from the W-2 genome. The three identified proteins Gt2929, Gt1378, and Gt1208 displayed optimal activities at high temperatures (70, 70, and 80 degrees C, respectively). Among these, Gt2929 exhibited excellent degradation capability, pH stability, and metal ion tolerance for nitronates under aerobic condition. Interestingly, under anaerobic condition, only Gt1378 still maintained high activity for 2-nitropropane and nitroethane, indicating that the W-2 strain utilized various pathways to degrade nitronates under aerobic and anaerobic conditions, respectively. Taken together, the first revelation of thermophilic nitroalkane-degrading mechanism under both aerobic and anaerobic conditions provides guidance and platform for biotechnological and industrial applications.
Keywords:Thermophilic bacterium;Geobacillus thermoglucosidasius;Thermophilic enzymes;Nitroalkane compounds;Anaerobic biodegradation