亮斑扁角水虻卵共生菌Bacillus velezensis的鉴定和产酶特征及其对幼虫分解餐厨垃圾效率的影响

Identification and enzyme profiling of black soldier fly egg commensal Bacillus velezensis and its effect on food waste bioconversion

摘要:

[目的] 从亮斑扁角水虻（Hermetia illucens L.）卵表筛选得到一株产多种酶的卵表共生菌，对该菌进行鉴定，并探究其最适生长条件、产酶特性及其对幼虫分解餐厨垃圾效率的影响。[方法] 通过多种选择性培养基筛选得到产多种酶的菌株。通过单因素实验方法确定其最适生长条件、产酶特性及其对幼虫分解餐厨垃圾效率的影响。[结果] 经过形态学观察、生理生化鉴定和16S rDNA序列分析，将该株亮斑扁角水虻卵表共生菌命名为贝莱斯芽胞杆菌（Bacillus velezensis EEAM 10B）。最适摇瓶培养条件为：40℃，200 r/min，pH 7.0，酵母浸粉10 g/L，葡萄糖10 g/L，培养16 h活菌数达3.1×10⁹ CFU/mL。进入稳定期后开始形成单端生芽胞，24 h后芽胞形成率95.8%。使用产酶筛选培养基培养结果表明：B.velezensis EEAM 10B菌株产木聚糖酶活性最强，其次是蛋白酶、纤维素酶、果胶酶、淀粉酶和植酸酶。按照1×10⁶ CFU/g用量添加B.velezensis EEAM 10B芽胞制剂到餐厨垃圾中饲养亮斑扁角水虻，B.velezensis EEAM 10B芽胞菌剂能够显著（P<0.05）提高亮斑扁角水虻幼虫对灭菌和非灭菌餐厨垃圾的转化效率，分别为13.4%和13.54%，但物料减少率没有显著差异（P>0.05）；显著提高灭菌餐厨垃圾中幼虫存活率至95%，提高非灭菌餐厨垃圾饲养幼虫的预蛹单重0.1437 g/只，化蛹率92.57%。[结论] B.velezensis EEAM 10B菌株能够产多种酶，且在亮斑扁角水虻处理餐厨废弃物中有潜在应用价值。

Abstract:

[Objective] A strain producing multiple enzymes was isolated from the egg surface of Hermetia illucens L. Further, the optimal growth conditions, enzyme-producing characteristics, and the effects of the strain on the food waste decomposition efficiency of Hermetia illucens L. were explored.[Methods] Enzyme-producing strains were obtained from various selective media. The optimal growth conditions, enzyme-producing characteristics, and the effects of it on the food waste treatment decomposition efficiency of Hermetia illucens L. were determined by the single-factor experiment. [Results] In this study, a Hermetia illucens L. egg-surface commensal bacterium was named as Bacillus velezensis EEAM 10B by morphological observation, biophysiological and biochemical tests, and 16S rDNA sequence analysis. The bacteria number was 3.1×10⁹ CFU/mL under the optimum growth conditions:40℃, 200 r/min, pH 7.0, 10 g/L yeast extract, 10 g/L glucose for 16 h. Approximately 95.8% single-terminal spores were formed after 24 h cultivation. Enzymes producing results are as follows:xylanase activity was the highest, followed by the protease, cellulase, pectinase, amylase, and phytase. Adding the Bacillus velezensis EEAM 10B spores to the food waste at a dosage of 1×10⁶ CFU/g significantly (P<0.05) improved the food conversion efficiency of black soldier fly larvae in both sterilized and non-sterilized food waste groups, reaching 13.4% and 13.54%, respectively, whereas the mass reduction rates did not present differences (P>0.05). Furthermore, in the sterilized food waste group, the survival rate of larvae and the prepupae weight were significantly increased to 95% and 0.1437 g per one, while the pupation rate reached 92.57% in the non-sterilized food waste group. [Conclusion] B. velezensis EEAM 10B strain can produce a variety of enzymes, and it has potential application value in the treatment of food waste with the black soldier fly.