Preparation, characterisation and cell viability of encapsulated Trichoderma asperellum in alginate beads.

Aim: The encapsulation of Trichoderma asperellum BRM-29104 using Ca-alginate matrix was evaluated.Methods: Intact and freeze-dried beads containing submerged conidia and microsclerotia (MS) of T. asperellum grown in liquid culture were prepared and characterised. Beads were stored at 8, 25, and 35 °C over 120 days.Results: The mean sizes of beads before and after freeze-drying were 2.5 ± 0.2 mm and 1.5 × 1.1 mm (± 0.1 mm), respectively. Freeze-dried beads stored at 8 °C were more effective in maintaining conidia concentration, while MS concentrations yielded 102 MS/g for both beads at 8 and 25 °C. The concentration of viable cells in freeze-dried beads stored at 8 °C attained 3.0 × 108 CFU/g after 120 days. FIRT analysis showed an interaction between the alginate and the cell wall of the fungus.Conclusion: These findings support the use of alginate beads followed by freeze drying and cold storage for maintenance of viability of T. asperellum.