Production of enzymes from potato pulp using batch operation of a bioreactor

Abstract

Trichoderma reesei strains MCG77 and Rut C30 were cultivated in batch operation in a stirred tank reactor on potato pulp (PP) consisting of starch, pectin, cellulose, and hemicellulose; potato pulp residue (PR) without starch and pectin; or enzymatic residue (ER), respectively, as substrate and potato protein liquor (PPL) as supplement. The enzyme mixtures produced by the fungi were characterized by four assays: with avicelase, CMCase, xylanase, and FP‐activities. Trichoderma reesei Rut C30 yielded higher activities than Trichoderma reesei MCG77. The enzyme activities and productivities obtained with PR are comparable to those obtained by other groups using pure cellulose and a synthetic nutrient solution in batch culture. An optimal operation strategy was derived to obtain maximum enzyme activity and productivity. After converting PR with the enzymes produced and using the residue, ER, as substrate for enzyme production, 85% (w/w) of the pulp was utilized.

Production of Edible Fungi from Potato Protein Liquor (PPL) in Airlift Bioreactor

“…PPL is described in the literature as a source of sugar and nitrogen for microorganisms [6,7,9,10]. The PPL used in this work was characterized by its concentration of sugars, nitrogen compounds, total solids, ashes, and COD.…”

“…The remaining liquor is concentrated to potato protein liquor (PPL) and consists of approximately 40% solids [6]. PPL is a severe challenge to wastewater treatment plants because of its high biological oxygen demand [7]. Currently, the side stream is stocked during the year to be used as a fertilizer during planting.…”

“…Alternative treatments have been suggested, attempting to find a destination for PPL, including using it as a substrate in different bioprocesses to produce yeast biomass [9], fungal protein [10], enzymes [7], and other metabolites [11]. However, the cultivation of filamentous fungi in this side stream has never been reported.…”

Techno-Economic and Life Cycle Assessment of Wastewater Management from Potato Starch Production: Present Status and Alternative Biotreatments

“…The reduced biological activity in the soil during this period prevents the uptake of the liquor, which forces the potato starch facilities to store large volumes of PPL for several months [9]. Additionally, the use of PPL as fertilizer causes contamination of groundwater and emits a bad odor that can disturb citizens living in neighboring areas [10]. However, as mentioned above, despite the high content of residual proteins in the PPL, they are of poor quality, hence preventing them from being used as a supplement for cattle feed [1].…”

“…The biodegradable nature of the byproduct has stimulated its use in bioprocesses to produce yeast biomass [11], acetate and ethanol [12], enzymes [10] and fungal protein [13]. Additionally, the filamentous zygomycete fungus Rhizopus oryzae has been used to reduce the chemical oxygen demand (COD) of the PPL and produce a protein-rich biomass with a potential application as fish feed [1].…”