A study was performed to investigate the efificiency of microbial inoculants after encapsulating in alginate supplemented with humic acid on plant growth. Two promising plant growth promoting rhizobacteria were identified by 16S rDNA sequencing as Pseudomonas putida CC-FR2-4 and Bacillus subtilis CC-pg104, which were further characterized by biochemical analyses and inoculated to Lectuca sativa L. seedlings as free cells and entrapped in beads. Significant increase in shoot height after 21 days of growth was observed with encapsulated CC-pg104 inoculated plants. Highest increase in root length was observed with CC-pg104 free-cell inoculated plants, followed by plants inoculated with encapsulated CC-pg104. Results clearly demonstrated that inoculation of the encapsulated bacterial isolates promoted plant growth similar to their respective free cells and could be a novel and feasible technique for application in agricultural industry. (c) 2006 Elsevier Ltd. All rights reserved.