Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Optimization of Media for the Production of Biomass and Pesticidal Metabolites by the Entomopathogenic Fungi Nomuraea rileyi (Farlow) Samson using Response Surface Methodology and Evaluation of their Biocontrol Potential against major Peanut Defoliator Spodoptera litura (Fab.) (Lepidoptera; Noctuidae)

S. Karthick Raja Namasivayam and R.S. Arvind Bharani

Department of Biotechnology, Sathyabama University, Chennai, Tamil Nadu, India.

Received on 06 April 2014 and accepted on 19 August 2014

 

ABSTRACT

Nomuraea rileyi (Farlow) Samson is an important fungal biocontrol agent and extensively used as mycoinsecticide against economic important insect pests in various parts of the world. Success of biocontrol agent is primarily based on the production of adequate quantity of inoculam using suitable media.Supply of nutrients is an important factor which influences the biomass production.Statistical optimization strategy as response surface methodology (RSM) is adopted to maximize the biomass production through submerged and solid state fermentation. RSM can identify the various interactions among different parameters and it has been extensively applied for optimization of cultural medium conditions and other process parameters in bio processes In the present study, Central composition design (CCD) was used for optimizing the parameters. Temperature (X?1?), pH (X2), Maltose (X3), Peptone (X4) was chosen as independent variables. The maximum percentage of biomass yield is obtained at 3.87g/mL of maltose and peptone at 0.55g/mL,temperature 28.1?C and pH 7.09.Metabolites were extracted from the culture filtrate of fungi grown in media and showed distinct effect on the life stages of Spodoptera litura. Lethal time 50(LT 50) and lethal concentration 50 (LC 50) was highly influenced by larval stages and concentration.

Keywords : Nomuraea rileyi, Spodoptera litura, Response surface methodology, Metabolites.