Insights on fungal solid-state fermentation for waste valorization: Conidia and chitinase production in different reactor configurations

Abstract

Different reactor configurations are paired with a wide variety of agro-industrial wastes of different biodegradability to produce fungal conidia by solid-state fermentation. This work presents a preliminary comparative study between packed-bed and tray reactor configurations to produce Beauveria bassiana and Trichoderma harzianum conidia using two different substrates in terms of biodegradability: rice husk or beer draff complemented with wood chips. Conidia production, mean temperature and respiration indexes have been analysed in most of the presented reactor configurations. Both strains showed higher conidia production when using beer draff complemented with wood chips as substrate due to the use of a mixture as substrate. When working with beer draff, chitinase analyses obtained similar profiles in both strains but higher overall values using TH. Conidia and chitinase production maximums were not achieved at the same time, having 2–3 days of difference depending on the strain. No significant differences in mean temperature were shown between most of the performed fermentations. As a result of the present work, further scaling of both packed bed and tray configurations using beer draff and wood chips to produce BB or TH conidia would be advisable. More experiments should be performed to optimize both conidia and chitinase productions to enhance the quality of the final product.