Production Protocol for Formulating Chitosan Enriched Oil Formulation of Beauveria bassiana (Bals.) Vuillemin
N. S. Nabeesath Beema *
Department of Entomology, College of Agriculture, Vellayani, India.
O. P. Reji Rani
Department of Entomology, College of Agriculture, Vellayani, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: The study aimed to develop an enriched oil formulation of Beauveria bassiana with enhanced conidial production and viability.
Study Design: The study comprised three experiments: (1) standardisation of media supplements, (2) standardisation of carrier materials and (3) standardisation of UV protectants for formulation development, each conducted using a completely randomised design.
Place and Duration of Study: Biocontrol Laboratory, Department of Entomology, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, Kerala Agricultural University, between December 2025 and October 2026.
Methodology: Three media supplements, namely crude chitin, crude chitosan and cricket protein powder, each at 5%, were evaluated for biomass, colony-forming units (CFU) and spore yield. Subsequently, sunflower oil, groundnut oil and sesame oil supplemented with 0.1% colloidal chitin or colloidal chitosan were evaluated as carriers using a conidial concentrate at a 65:35 ratio. The selected carrier combination was further evaluated with India ink 1%, fabric whitener 0.5% and Congo red 1% as UV protectants. CFU and spore count were assessed during the observation.
Results: Crude chitosan (5%) and cricket protein powder (5%) were equally effective in enhancing the growth and sporulation of the fungus when supplemented in PDB, compared to crude chitin (5%). Crude chitosan (5%) and cricket protein powder (5%) supported significantly higher biomass, spore count and CFU, recording 1.25 and 1.40 g biomass, 2.45 and 2.97 × 10⁸ spores mL⁻¹, and 1.32 and 1.45 × 10⁵ CFU mL⁻¹, respectively. Crude chitosan was selected based on its availability and economic feasibility. Among carrier combinations, groundnut oil supplemented with 0.1% colloidal chitosan recorded the highest spore count (2.76 × 10¹⁰ spores mL⁻¹) and CFU (2.59 × 10⁶ CFU mL⁻¹) after six weeks. India ink (1%) was the most effective UV protectant, retaining 1.04 × 10¹⁰ spores mL⁻¹ and 1.25 × 10⁶ CFU mL⁻¹ after 28 days.
Conclusion: The study concluded that crude chitosan is the best supplement in PDB for enhancing the growth and yield of B. bassiana. For developing an oil formulation, groundnut oil is the best carrier, with 0.1% colloidal chitosan as the best additive. Conidial viability and performance can be further protected by adding 1% India ink.
Keywords: Beauveria bassiana, chitosan, carrier, UV protectant, India ink