Microencapsulated biofertilizer formulation: product development and effect on growth of green pepper seedlings

Aim of the study: This study aimed to formulate a novel, commercially applicable biofertilizer, to optimize the microencapsulation procedure of Bacillus subtilis NCIM 2063 and examine the stability and phytostimulatory effects of obtained formulation. Area of the study: Southestern Serbia. Material and methods: Microbial powder formulations were prepared using spray drying with maltodextrin as a carrier. The spray drying conditions were set according to Box-Benkhen experimental desing. The effect of the formulation was tested on green pepper (Capsicum annuum) seeds in controled conditions. Main results: Response surface models were developed. All of the models were statistically significant, adequately fitted and reproducible. The maximum achieved values of viability and yield in a formulation were 1.99·109 CFU/g and 96.8%, respectively, whilst the driest formulation had 1.44% moisture. The following optimum conditions were proposed for the spray drying procedure: an inlet air temperature of 133 °C, maltodextrin concentration of 50 g/L and a feed flow rate of 6.5 mL/min. The obtained microbial formulation had a high survival rate after being stored at room temperature over a 1--year period. Its application on green pepper seeds had beneficial effect on plant height, leaf dry weight and chlorophyll content of the seedlings. Research highlights: B. subtilis was successfully microencapsulated on maltodextrin as a carrier. Interaction effects between the process variables were fully explained and statistically significant models were developed. In addition to biocontrol properties formulation had a phytostimulatory effect, excellent stability and satisfactory physical properties.