Strain improvement of Aspergillus terreus for hyper-production of lovastatin and immobilization of mutant ATU-06 strain for repeated batch culture process

The aim of this work was to hyper-produce lovastatin by strain improvement of Aspergillus terreus S-24 through UV mutagenesis using corn cobs as carrier substrate in solid state fermentation. Ten positive mutants were selected on agar plates for still plate experiments. ATU-06 mutant strain showed 45.63 ± 1.74 mg/100 mL lovastatin concentration higher than parent strain (18.74 ± 1.68 mg/100 mL) in pre-optimized fermentation medium. Fermentation parameters pH (6), temperature (30°C), inoculum size (2 mL) moisture contents (60%) and incubation time (120 h) were optimized for both mutant and parent strains. Kinetic growth parameters also showed that mutant strain ATU-06 showed greater stability and improved results as compared to parent strain. Finally, the mutant Aspergillus terreus ATU-06 strain was immobilized by entrapping it in calcium alginate beads and agar for repeated use.