Takei Takayuki, Yoshida Masahiro, Hatate Yasuo, Shiomori Koichiro, Kiyoyama Shiro
Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
J Biosci Bioeng. 2008 Sep;106(3):268-72. doi: 10.1263/jbb.106.268.
Free plant growth-promoting bacteria in soil bioamendments (SBA) are easily outnumbered by competitors and predators in agricultural soils. Microencapsulation of the bacteria is an effective technique that provides a suitable microenvironment for their survival. In this study, we attempted to prepare poly(epsilon-caprolactone) (PCL) microcapsules enclosing lactic acid bacteria (LAB), a plant growth-promoting bacteria, using the solvent-evaporation method via water-in-oil-in-water (W/O/W) emulsion. Three preparation parameters in the emulsion system were optimized based on the lactic acid production activity of the encapsulated LAB. A sodium alginate aqueous solution suspending the bacteria, a dichloromethane solution with dissolved PCL, and a poly(vinyl alcohol) aqueous solution were used as the inner aqueous phase (W(i)), the oil phase (O), and the outer aqueous phase (W(o)), respectively. Suitable volume ratio of W(i) to O, concentration of sodium alginate in W(i), and the molecular weight of PCL in O were 0.1, 1.0%, and 40 kDa, respectively. The lactic acid production activity of the microcapsules prepared under the optimized conditions was approximately nine times higher than that of commercial SBA. Application to soil demonstrated that the microcapsules are effective in the removal of the root-knot nematodes.
土壤生物改良剂（SBA）中促进植物生长的游离细菌在农业土壤中很容易被竞争者和捕食者超过。细菌的微囊化是一种有效的技术，可为其生存提供合适的微环境。在本研究中，我们试图通过水包油包水（W/O/W）乳液的溶剂蒸发法制备包裹乳酸菌（LAB，一种促进植物生长的细菌）的聚（ε-己内酯）（PCL）微胶囊。基于被包裹LAB的乳酸产生活性，对乳液体系中的三个制备参数进行了优化。悬浮细菌的海藻酸钠水溶液、溶解有PCL的二氯甲烷溶液和聚乙烯醇水溶液分别用作内水相（W(i)）、油相（O）和外水相（W(o)）。W(i)与O的合适体积比、W(i)中海藻酸钠的浓度以及O中PCL的分子量分别为0.1、1.0%和40 kDa。在优化条件下制备的微胶囊的乳酸产生活性比市售SBA高约九倍。在土壤中的应用表明，这些微胶囊在去除根结线虫方面是有效的。
