Revalorization of green tea waste through the production of cellulases by solid-state fermentation using a Aspergillus niger 28A

Revalorization of green tea residues (GTR) was carried out through cellulase production by solid- state fermentation (SSF) using Aspergillus niger 28A. An exploratory study in the production of endocellulases (EC), beta-glucosidases (BG), and total cellulase activity (FPUase) was carried out. The effect of operational conditions as moisture, temperature, and kinetic time was evaluated. The BG was partially purified by dialysis and ultracentrifugation, and the optimal pH and temperature for its activity were determined. It was found that A. niger 28A produced high titers of EC (65.85 +/- 2.18 IU/g), FPUase (5.44 +/- 0.11 FPU/g), and BG activities (1,016.52 +/- 3.58 IU/g) in the exploratory analysis. The best operational conditions for enzymes production were 34 degrees C and 96 h for EC and FPUase activities, and 32 degrees C, 65% moisture, and 120 h for BG activity, respectively. After the partial purification process, the BG reached a specific activity of 496.90 +/- 75.04 IU/mg. The optimal conditions for BG activity from the partially purified extracts were pH 4 and 60 degrees C. GTR constitutes a suitable biomass and substrate in the production of cellulase, reaching high titers of BG, proposing a way for its revalorization through the generation of high added value products as enzymes for the depolymerization of cellulose.

Automated summary

Revalorization of green tea residues (GTR) was achieved through solid-state fermentation (SSF) using Aspergillus niger 28A for cellulase production. An exploratory study demonstrated the high titers of endocellulases (EC), beta-glucosidases (BG), and total cellulase activity (FPUase) produced by A. niger 28A. Optimal operational conditions were determined for each enzyme activity, and after partial purification, BG reached a specific activity of 496.90 +/- 75.04 IU/mg. Green tea residues prove to be a suitable biomass and substrate for cellulase production, offering a way for revalorization and the generation of high-value enzymes.