Sand washing of oil spill-affected beaches using concentrated β-glucans obtained from residual baker's yeast

Valorization of residual yeast of the bakery industry for use in the remediation of oil-contaminated soils as an emulsifier is a biocompatible and effective process that will reduce environmental pollution. The aim of this study was to use concentrated β-glucan obtained from residual baker's yeast, Saccharomyces cerevisiae, as an emulsifier to remove total petroleum hydrocarbons (TPH) from the contaminated sands of two beaches affected by the oil spill that occurred in January 2022 north of Lima, Peru. The extraction and concentration of β-glucan from sand were performed at a pilot scale using autolysis with 3 % sodium chloride, temperature elevation, treatment with organic solvents and water, hydrolysis via proteases, and vacuum filtration. The chemical composition and functional properties of concentrated β-glucan were evaluated to determine its quality and efficacy. In addition, the values of TPH removal efficiency obtained using concentrated β-glucan, water, and the commercial emulsifier Tween-80 were compared. The mass recovery of concentrated β-glucan was 5.59 %, with a β-glucan content of 38.60 %. The efficiency of ex-situ removal of TPH from hydrocarbon-impacted sands containing 78323 mg/kg of TPH reached 50 % and 70 % when the concentrated β-glucan concentrations used were 70.3 % and 80.3 %, respectively. These efficiency values are higher than those obtained when water was used for TPH removal but lower than those obtained when Tween-80 was used for TPH removal.