The Use of Selected Strains of Yeasts in the Treatment of Processing Wastewater From Lye-Peeled and Steam-Peeled Potatoes

Abstract

The feasibility of using suitable strains of yeast cultures to reduce the wastewater strength of potato processing effluent and the recovery of the biomass produced by the microorganisms was studied. Effective chemical oxygen demand (COD) reduction was achieved in lye‐peeled and steam‐peeled potato effluents by fermentation with the yeast S. fibuliger ATCC 9947. The COD of the actively fermented activated wastewater from lye‐peeled potato was reduced by 69, 79 and 85% of the initial values after 24, 48 and 72 h of fermentation, respectively. Using steam‐peeled potato effluent, 85% of the initial COD was reduced after 24 h of fermentation. Greater reductions in COD were achieved by centrifugation of the fermented wastewater samples. The centrifuged yeast solids recovered from the fermented steam‐peeled potato effluent ranged from 1.55 to 2.0 g/l (dry wt.) after 6 to 28 h of fermentation, and had a crude protein content of 29 to 31%.

Production of Microbial Biomass Protein from Potato Processing Wastes by Cephalosporium eichhorniae

“…In the Swedish Symba process (9) the amylolytic fungus Saccharomycopsis fibuligera is grown together with C. utilis; the former species hydrolyzes the starch, and the latter grows rapidly on the sugars released. More recent evaluations of this process (10,14,19) suggest that this process is only partially successful when applied to potato wastes. An amylolytic strain of Canadida tropicalis has been reported to convert starchy substrates into cell mass in a single stage (24), but its use on potato wastes has not been described.…”

“…For example, the Symba process applied to whole (rejected) potatoes gave a product with 40% crude protein and a biomass yield of 60% of the available starch (9). The biomass obtained by Karim and Sistrunk (10) from steampeeled potato effluent waste water contained only 29 to 31% crude protein when a Symba-like process was employed. The product they obtained with Neurospora sitophila contained 39% crude protein (11).…”

Análisis de las variables que afectan el desarrollo de microorganismos filamentosos en sistemas de barros activados para el tratamiento de efluentes de la industria alimenticia

“…La alta carga orgánica de las aguas residuales provenientes de las industrias procesadoras de vegetales genera un serio problema de contaminación cuando es descargada sin ningún tipo de tratamiento a ríos y mares. Con la aparición de leyes que limitan la descarga de contaminantes, las industrias fueron forzadas a encontrar un tratamiento previo de sus residuos (Karim y Sistrunk 1984.…”