Isolation and Characterization of a New Ferulic-Acid-Biotransforming Bacillus megaterium from Maize Alkaline Wastewater (Nejayote)

Abstract

Nejayote is an alkaline wastewater generated during the nixtamalization process. Nejayote contains high-value compounds such as ferulic acid (FA), which is widely employed as a substrate for the biotechnological production of flavors and aromas. In the present study, the isolation, identification, and characterization of a native strain of Bacillus megaterium were performed, and its capacity to produce 4-vinylguaiacol (4VG) from ferulic acid was evaluated by employing growing cell and resting cell systems. Growing cells of native B. megaterium biotransformed 6 mM crude FA in nejayote into 2.1 mM 4VG, reaching a productivity of 0.21 mM h−1 4VG, while nejayote enriched with FA at 10, 15, and 25 mM resulted in the formation of 2.4, 3.8, and 6.2 mM 4VG and productivities of 0.24, 0.38, and 0.51 mM h−1 4VG, respectively. In the resting cell system, from 6 and 25 mM pure FA, 3.5 mM 4VG was produced (0.18 mM h−1 4VG), while at 10 and 15 mM FA, 4.6 and 5.1 mM 4VG (average of 0.24 mM h−1 4VG) were obtained, respectively. The native B. megaterium strain, isolated from nejayote, showed great biotechnological potential to produce 4VG from crude FA contained in this wastewater, in which other Bacillus species, such as B. licheniformis and B. cereus, were unable to grow and biotransform FA into 4VG.