Abstract
Cheese whey results as by product of cheese or casein production in large amounts. Depending on the ceesemaking process, the amount can rise to more than 6 times, on a weight basis, the cheese produced.
Cheese whey has considerable nutritional value and a strong organic and saline content, such to pose serious disposal problems. The Chemical Oxygen Demand (COD) can be as high as 100 kg m-3, a value so high to make impossible the direct disposal in superficial water and to make critical any biological treatment withoutprevious dilution. Many cheese whey components have significant value in the light of their direct use (proteins, lactose), or as a feedstock to obtain building blocks or chemicals (lactose fermentation to ethanol, lactic acid ecc.). In this paper a conceptual process for the valorisation of whey through the recovery of added value components is presented. The process includes lipids recovery via thermocalcic precipitation, protein recovery via ultrafiltration and lactose valorisation through biological processes to obtain polyhydroxyalcanoates (PHA) and/or Lactic Acid (LA). In this work many of the unit operation of the process were developed and optimized at a lab scale. Ultrafiltration with 10 kDa membranes allowed to obtain a stream having protein concentration of more than 80 g/l, permeate fermentation led to obtain a biomass concentration of more than 1,5 g/l with a PHA content ranging between 50-60%. A first attempt of a mass flow balance of the entire process can be drawn.
