杜比亚蟑螂肠道菌的分离鉴定及产消化酶功能菌株的筛选

Isolation and identification of gut bacteria from Blaptica dubia and screening of digestive enzyme-producing strains

摘要:

【背景】杜比亚蟑螂(Blaptica dubia)可用于活体饲料、化妆品和医药保健品的生产，其肠道菌的研究对杜比亚蟑螂的饲养和肠道菌资源的开发与利用都十分重要。【目的】揭示杜比亚蟑螂肠道可培养菌的种类，筛选具有产消化酶功能的菌株，为理解肠道菌对宿主的影响机理及功能菌株的利用提供科学依据和研究材料。【方法】采用体外培养法获得杜比亚蟑螂肠道菌，结合形态学和分子生物学方法进行鉴定；用水解圈法分别筛选产纤维素酶、蛋白酶、脂肪酶和淀粉酶菌株。【结果】在杜比亚蟑螂肠道中共分离出4属7种细菌，其中芽孢杆菌属(Bacillus)2种，沙雷氏菌属(Serratia)和柠檬酸杆菌属(Citrobacter)各2种，肠球菌属(Enterococcus)1种。从获得的20个菌株中筛选出10个具有产消化酶功能的菌株。其中，芽孢杆菌属的菌株D6、D12和D20具有产纤维素酶、蛋白酶、淀粉酶及脂肪酶4种消化酶的功能；沙雷氏菌属的菌株D3、D7、D9、D11和D15具有产纤维素酶、蛋白酶和脂肪酶3种消化酶的能力；柠檬酸杆菌属的菌株D5具有产纤维素酶的功能；肠球菌属的菌株D17具有产蛋白酶的能力。【结论】杜比亚蟑螂肠道多种细菌具有产消化酶帮助降解大分子营养物质的功能，可通过协助食物消化影响宿主健康。菌株D12、D7和D11分别具有最强产纤维素酶、蛋白酶和脂肪酶的能力，是可进一步开发利用的肠道功能菌株资源。

Abstract:

[Background] Blaptica dubia can be used for producing living feed, cosmetics, and healthcare products. Studying the gut bacteria is essential for the breeding of B.dubia and development and utilization of gut bacterial resources. [Objective] To disclose the culturable bacterial species from the gut of B.dubia, and the strains capable of producing digestive enzymes, so as to provide a scientific basis and research materials for research on the influence of gut bacteria on the host and for utilization of the functional bacterial strains. [Methods] The gut bacteria of B.dubia were isolated with the culture method and identified via the methods of morphology and molecular biology. The hydrolysis circle method was employed to screen out the strains capable of producing cellulase, protease, amylase, and lipase, respectively. [Results] A total of 7 species of bacteria belonging to 4 genera were isolated from the gut of B.dubia, including 1 species of Enterococcus, 2 species of Bacillus, 2 species of Serratia, and 2 species of Citrobacter. Ten strains capable of producing digestive enzymes were screened out from the obtained 20 strains. Among them, Bacillus strains D6, D12, and D20 can produce all the 4 digestive enzymes. Serratia strains D3, D7, D9, D11, and D15 had the ability to produce 3 digestive enzymes: cellulase, protease, and lipase. Citrobacter strain D5 and Enterococcus strain D17 can produce cellulase and protease, respectively.[Conclusion] A variety of bacteria in the gut of B.dubia can produce digestive enzymes to help degrade macromolecular nutrients, which may affect the health of host by assisting food digestion. Strains D12, D7, and D11 have the strongest ability to produce cellulase, protease, and lipase, respectively, and are the gut functional strain resources worthy of further development and utilization.