一株高效几丁质降解菌蜡样芽孢杆菌BSF-CH1的分离鉴定及其在黑水虻蛹壳生物转化中的应用

An efficient chitinolytic bacterium Bacillus cereus BSF-CH1: isolation, identification, and application in puparium biotransformation of Hermetia illucens

摘要:

黑水虻(Hermetia illucens)养殖产生的蛹壳富含几丁质和蛋白质，但目前缺乏高效环保的利用方法。目的 从黑水虻蛹壳堆中分离筛选几丁质降解菌，探索其在蛹壳生物转化中的应用潜力。方法 使用平板筛选和16S rRNA基因测序进行分离和鉴定，采用3,5-二硝基水杨酸(3,5-dinitrosalicylic acid, DNS)法检测其酶活力。使用PacBio HiFi技术进行全基因组测序，以阐明其降解机制。通过蛹壳发酵实验探索其应用潜力。结果 共鉴定得到7株分离菌，其中活性最强的菌株为蜡样芽孢杆菌(Bacillus cereus) BSF-CH1，该菌株在发酵第2天时几丁质酶活力达到最高值0.48 U/mL。全基因组测序结果显示BSF-CH1含有3个几丁质酶(chitinase)基因、7个几丁质脱乙酰酶(chitin deacetylase)基因及4个壳糊精酶基因(chitodextrinase)。蛹壳生物转化实验表明，BSF-CH1能在7 d内将蛹壳质量降解47.2%，几丁质和蛋白质的降解率分别达到64.6%和59.1%。结论 本研究报道了从黑水虻蛹壳中分离的高效几丁质降解菌，为蛹壳的生物转化利用提供了新思路，对促进黑水虻产业的可持续发展具有重要意义。

Abstract:

The puparium of Hermetia illucens is rich in chitin and protein, while efficient and environmentally friendly utilization methods remain to be developed.Objective To isolate chitinolytic bacteria from the puparium pile of H. illucens and explore their potential in puparium biotransformation.Methods Strains were isolated by the plate screening method and identified by 16S rRNA gene sequencing. The 3,5-dinitrosalicylic acid (DNS) method was employed to determine the chitinase activity. Whole genome sequencing by PacBio HiFi was conducted to elucidate the degradation mechanism. The application potential of the strain was explored by puparium fermentation experiments.Results Among the seven isolated strains, Bacillus cereus BSF-CH1 showed the highest chitinase activity, reaching a maximum chitinase activity of 0.48 U/mL on the second day of fermentation. The genome of BSF-CH1 contained three chitinase genes, seven chitin deacetylase genes, and four chitodextrinase genes. Puparium biotransformation experiments showed that BSF-CH1 could degrade 47.2% of puparium mass within 7 days, with degradation rates of 64.6% and 59.1% for chitin and protein, respectively.Conclusion This study reports an efficient chitinolytic bacterium isolated from the puparium of H. illucens, providing new insights into the puparium biotransformation and having important implications for promoting the sustainable development of the H. illucens industry.