Adetunji Charles, Oloke Julius, Kumar Anil, Swaranjit Singh, Akpor Benjamin
Department of Biological Sciences, Applied Microbiology, Biotechnology and Nanotechnology Laboratory, Landmark University, P.M.B. 1001, Omu Aran, Kwara State, Nigeria.
Department of Pure and Applied Biology, Ladoke Akintola University of Technology, P.M.B 4000, Ogbomoso, Oyo State, Nigeria.
Environ Sci Pollut Res Int. 2017 May;24(15):13700-13709. doi: 10.1007/s11356-017-8983-8. Epub 2017 Apr 10.
Rhamnolipid (Rh) is a biosurfactant produced by the bacterial Pseudomonas aeruginosa. This present study investigates rhizospheric strain C1501 of P. aeruginosa with an accession number KF976394 with the best production of rhamnolipid: a biosurfactant. The partially purified rhamnolipid from strain C1501 and Tween 80 was tested on mycelial growth of wild strain C1136. The enzyme activities involved in biodegradation, as well as necrosis induction on the tested weeds, were performed using scanning electron microscopy. It was observed that the different concentrations of rhamnolipid tested enhanced the dry mycelia weight yield of Lasiodiplodia pseudotheobromae which has been established to be producing a phytotoxic metabolite for killing weeds. It was observed that strain C1136 had a high level of cellulase and xylanase enzyme activities during this study. The scanning electron microscopy showed that the mutant strain of C1136 combined with 0.003% v/v of rhamnolipid enhances biodegradability and a high level of necrosis on the tested weeds compared with that on the untreated weeds. The highest CMCase activities and xylanase activities were obtained on the fourth day from the phytotoxic metabolite produced from the mutant strain of L. pseudotheobromae when combined with 0.003% v/v of rhamnolipid. This study has shown that rhamnolipid can serve as an adjuvant in order to enhance the penetrability of bioherbicide active ingredient for controlling weeds.
鼠李糖脂（Rh）是由铜绿假单胞菌产生的一种生物表面活性剂。本研究调查了保藏编号为KF976394的铜绿假单胞菌根际菌株C1501，其鼠李糖脂（一种生物表面活性剂）产量最高。对从菌株C1501中部分纯化得到的鼠李糖脂和吐温80进行了对野生菌株C1136菌丝生长的测试。利用扫描电子显微镜对参与生物降解的酶活性以及受试杂草上的坏死诱导情况进行了检测。结果发现，所测试的不同浓度鼠李糖脂提高了拟可可球座菌的干菌丝重量产量，该菌已被证实能产生一种用于杀死杂草的植物毒性代谢物。在本研究过程中观察到，菌株C1136具有高水平的纤维素酶和木聚糖酶活性。扫描电子显微镜显示，与未处理的杂草相比，C1136突变株与0.003% v/v的鼠李糖脂结合可提高生物降解性，并使受试杂草上出现高水平的坏死现象。当与0.003% v/v的鼠李糖脂结合时，从拟可可球座菌突变株产生的植物毒性代谢物在第四天获得了最高的羧甲基纤维素酶活性和木聚糖酶活性。本研究表明，鼠李糖脂可作为一种助剂，以增强生物除草剂活性成分对杂草的控制渗透能力。
