Abstract:The monoglyceride lipase GMGL derived from Bacillus licheniformis was used as the research object. The fermentation conditions of recombinant Escherichia coli bacteria were optimized in a 5 L bioreactor, and the best inductive culture conditions were determined: inductive temperature 25 ℃, the pH of the fermentation mediumwas 7.0, the bacterial OD600 reached 20, and the final concentration of IPTG was 1 mmol/L. The glucose feeding method was variable speed feeding. After 24 hours of induction culture, the wet weight of the bacterial cell reached 125.40 g/L, and the fermentation activity was 1985 U/mL, which increasedby 67.5% compared to the pre-optimization period (1185 U/mL). Further immobilization studies were carried out on GMGL, and the optimal immobilization conditions were determined as follows: enzyme load was 100 mg/g, phosphate buffer salt concentration was 0.50 mol/L, and pH was 9. After optimization, the activity of immobilized GMGL was 4770 U/g, which increasedby 189.09% compared to that before optimization (1650 U/g). Using scanning electron microscopy (SEM) and Fourier infrared spectroscopy (FT-IR) for characterization, it was confirmed that GMGL was successfully loaded on ECR8285. These results will provide a research basis for the efficient preparation of monoglyceride lipase with high activity.
