Objective: The aim of this work was to purify and identify the β-glucanase active protein from the fermentation supernatant of Bacillus velezensis 2-6 which originated from mangrove, and to investigate the enzymatic characteristics of the purified β-glucanase active protein. Methods: The ammonium sulfate precipitation method and DEAE-Sepharose Fast Flow ion-exchange chromatography were used to purify the β-glucanase active protein from the supernatant of Bacillus velezensis 2-6. LC-MS/MS analysis was used to identify the purified protein. The enzyme activity of β-glucanase active protein was analyzed using DNS method. Thin layer chromatography was used to detect the degradation level of β-glucanase active protein on laminarin. Filter paper method was used to analyze the antibacterial activity of β-glucanase active protein on pathogenic microorganisms. Results: A protein with a molecular weight of approximately 45 kDa was obtained from strain 2-6 fermentation supernatant by 80% ammonium sulfate precipitation and DEAE-Sepharose Fast Flow ion-exchange chromatography, and the β-glucanase activity of this protein reached 36956.5 U/mg. The purified protein was deduced as glucuronic acid xylanase by LC-MS/MS which consisted of 423 amino acids and named as GxylE-v26. The optimal enzyme reaction temperature of GxylE-v26 was 60 ℃ and the optimal pH was 4. Low concentration of Fe2+ (1 mmol/L) could promote the enzyme activity of GxylE-v26 while medium (10 mmol/L) and high (100 mmol/L) concentration of Fe2+, Ca2+, Mg2+ and Ba2+ could inhibit the enzyme activity of GxylE-v26. GxylE-v26 could hydrolyze laminarin and exhibit inhibitory effects on the growth of Staphylococcus aureus and Pantoea ananatis. The inhibition zone diameters of 1 mg/mL GxylE-v26 against S. aureus and P. ananatis were 1 cm and 1.1 cm, respectively. Conclusion: A β-glucanase active protein, named GxylE-v26, was purified and identified from the fermentation supernatant of Bacillus velezensis 2-6 which derived from mangrove. GxylE-v26 was an acid enzyme which could tolerate a certain degree of high temperature and possess antimicrobial activity against Staphylococcus aureus and Pantoea ananas.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |