Young Chiu-Chung, Rekha P D, Lai Wei-An, Arun A B
Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung, Taiwan, ROC.
Biotechnol Bioeng. 2006 Sep 5;95(1):76-83. doi: 10.1002/bit.20957.
The key to achieving successful, reproducible results following the introduction of beneficial microbes into soil relies on the survival rate of the inoculated bacteria in a heterogeneous soil environment and hence an improved encapsulation method was developed. Owing to the constraints associated with the inoculum formulation, in this study, encapsulation of a plant growth promoting bacteria (PGPB) isolate Bacillus subtilis CC-pg104 was attempted with alginate by enriching the bead microenvironment with humic acid. High viability of the encapsulated bacteria was observed with minimum cell loss upon storage for 5 months. Steady and constant cell release from the bead was observed for 1 week at different pH. Encapsulated cells remained active as evidenced by their ability to solubilize calcium phosphate in vitro. Successful plant growth promotion of lettuce by the encapsulated bacteria under gnotobiotic and sterile environment was also achieved. Feasibility of this improved encapsulation technique is mainly due to the dual benefits of humic acid to microbe and plant and its chemical properties allowing an easy mixing with alginate without interfering in the formation of the alginate gel beads by cross-linking with Ca2+ ions. Thus, the encapsulation method described in this study can be effectively used to protect the PGPB inoculum from adverse conditions of the soil for their successful establishment in the rhizosphere.
在向土壤中引入有益微生物后，要获得成功且可重复的结果，关键在于接种细菌在异质土壤环境中的存活率，因此开发了一种改进的包封方法。由于接种剂配方存在限制，在本研究中，尝试通过用腐殖酸丰富珠粒微环境，以海藻酸盐包封一种促进植物生长的细菌（PGPB）分离株枯草芽孢杆菌CC-pg104。观察到包封细菌具有高活力，储存5个月后细胞损失最小。在不同pH值下，观察到珠粒在1周内稳定且持续释放细胞。包封细胞在体外具有溶解磷酸钙的能力，证明其保持活性。在无菌和无菌环境下，包封细菌也成功促进了生菜的生长。这种改进的包封技术的可行性主要归因于腐殖酸对微生物和植物的双重益处及其化学性质，使其易于与海藻酸盐混合，而不会通过与Ca2+离子交联干扰海藻酸盐凝胶珠的形成。因此，本研究中描述的包封方法可有效地用于保护PGPB接种剂免受土壤不利条件的影响，以便其在根际成功定殖。
