Optimization of solid-state fermentation process of Trichoderma atroviride TA-9 by response surface methodology

In preliminary study, a Trichoderma atroviride strain TA-9 was isolated which was proved as a potential biocontrol agent. To optimize the solid-state fermentation media and conditions for T. atroviride strain TA-9, the Plackett-Burman experiments and response surface methodology were employed. The results showed that: i) Sucrose, ammonium sulfate and potassium dihydrogen phosphate were considered as dominant elements in the fermentation media. ii) While, culture temperature, concentration of inoculated conidia and moisture content were determined as dominant culture conditions. iii) The optimized medium was composed of 30% wheat bran, 20% rice hull, 24.65% sucrose, 0.88% ammonium sulfate, 0.88% potassium dihydrogen phosphate, 1% soybean meal, 0.5% mineral mixture, and 0.3% casein enzymatic hydrolysate. iv) The optimized fermentation conditions were described in the following: inoculate 5.2 × 10⁵ conidia that harvested from 6-day culture per gram media for start, 48.1% moisture content in media, culture in the light at 24.1 ℃, stir well after 60 hours cultured and further culture till 8 days. The conidia yield was up to 2.44 × 10¹⁰ conidia per gram media which was slightly higher than forecast yield (2.24 × 10¹⁰ conidia per gram media).