Characterization of Cheese whey Effluents and Investigation of Their Potential to be used as a Nutrient Substrate for Chlorella Biomass Production

The aim of the present study was the characterization of three different types of cheese-whey (CW) effluents, originating from the production of different Greek goat and sheep cheese types, and the detailed design of CW based media for Chlorella biomass production. One of these CW originated from the primary stage (PCW) and two from the second stage (SCW) of cheese production. Initially, the experimental approach included the detailed characterization of these CW fractions by well established methods. On the second part of this work, CW-based media were designed and used for Chlorella biomass production. It has been shown through this study that CWs exhibit a high polluting potential by exhibiting a high concentration of solids (1.5-5.7 g L-1), organic carbon (25-34.1 g L-1) as well as biochemical and chemical oxygen demand (26-37.5 and 65.394.1 g L-1 respectively). Furthermore, CW types exhibited 0.79-2.52 g L-1 nitrogen, 366-549 mg L-1 phosphorous and 56.6-80.1 g L-1 lactose. Chlorella cultivation experiments showed that the addition of a trace minerals solution was crucial to achieve cell growth was. Chlorella cultivated in PCW exhibited high photosynthetic efficiency and the growth was comparable to that of control cultures. On the other hand, the increase of salt concentration in SCW caused a decrease of cell growth and photosynthetic efficiency. It was shown through this study that the detailed characterization of a wastewater type, as well as the detailed design of media, are the most important steps to achieve an algal biomass production, with perspective applications the valorization of CW. [GRAPHICS]

Automated summary

The study aimed to characterize three types of cheese-whey effluents and design CW-based media for Chlorella biomass production. The study revealed that CWs have a high polluting potential with high concentrations of solids, organic carbon, and oxygen demand. The addition of a trace minerals solution was crucial for cell growth, and different types of CW had different effects on algae growth and photosynthetic efficiency.