Solid-state cultivation (SSC) is microbial growth on solid supports under limited water conditions. Citric acid, one of the products obtained by SSC, is a microbial aerobic metabolic product with various industrial applications. Several wastes from agro-industries are used in SSC, such as sugarcane bagasse and vinasse. As xylanolytic enzymes of inoculum breakdown the lignocellulosic material (bagasse), mixed fungal cultures or co-cultures are used in these SSC. Thus, this study aims to evaluate the effect of inoculum (Aspergillus niger and Trichoderma reesei consortium) in the production of citric acid from sugarcane bagasse impregnated with vinasse using bench packed bed reactors (PBR). The results show the importance of T. reesei in inoculum with A. niger at a ratio of 50:50 and 25:75, suggesting the use of solid support due to the complementation of the hydrolytic enzymes. The highest concentration of approximately 1000 mg L− 1 of citric acid yield for 100 mm of bed height in 48 and 72 h, with the maximum yield from glucose to citric acid (2.2 mg citric acid mg glucose−1). kLa indicates that maintaining solid moisture and liquid film thickness is important to keep the oxygen transfer in SSC.

Solid-state cultivation (SSC) is microbial growth on solid supports under limited water conditions. Citric acid, one of the products obtained by SSC, is a microbial aerobic metabolic product with various industrial applications. Several wastes from agro-industries are used in SSC, such as sugarcane bagasse and vinasse. As xylanolytic enzymes of inoculum breakdown the lignocellulosic material (bagasse), mixed fungal cultures or co-cultures are used in these SSC. Thus, this study aims to evaluate the effect of inoculum (Aspergillus niger and Trichoderma reesei consortium) in the production of citric acid from sugarcane bagasse impregnated with vinasse using bench packed bed reactors (PBR). The results show the importance of T. reesei in inoculum with A. niger at a ratio of 50:50 and 25:75, suggesting the use of solid support due to the complementation of the hydrolytic enzymes. The highest concentration of approximately 1000 mg L − 1 of citric acid yield for 100 mm of bed height in 48 and 72 h, with the maximum yield from glucose to citric acid (2.2 mg citric acid mg glucose −1 ). k L a indicates that maintaining solid moisture and liquid lm thickness is important to keep the oxygen transfer in SSC.