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Encapsulation of plant growth‐promoting bacteria in alginate beads enriched with humic acid
Author(s) -
Young ChiuChung,
Rekha P.D.,
Lai WeiAn,
Arun A.B.
Publication year - 2006
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20957
Subject(s) - bacteria , rhizosphere , bacillus subtilis , chemistry , humic acid , phosphate , bacterial growth , calcium alginate , plant growth , biofilm , food science , calcium , biochemistry , botany , biology , fertilizer , genetics , organic chemistry
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 Ca 2+ 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. © 2006 Wiley Periodicals, Inc.