Exploiting Cheese Whey as Co-substrate for Polyhydroxyalkanoates Synthesis from Burkholderia sacchari and as Raw Material for the Development of Biofilms

Abstract

Cheese whey, a residue from dairy industry, was investigated (1) as co-substrate for polyhydroxyalkanotes (PHA) synthesis by Burkholderia sacchari LFM 101 and (2) as raw material for biofilms production. The strain was studied in kinetic terms at 30 and 35 °C, with better conditions found at 35 °C. Cultures with cheese whey as co-substrate presented lower growth than cultures using glucose as the only source of carbon. Lactose was then evaluated as co-substrate, since it is the main component of cheese whey. Results indicated that it could be repressing the consumption of glucose in the cultures containing cheese whey. Thus, glucose was utilized as sole carbon source for PHA production at 35 °C. 3-hydroxybutyrate (3-HB) was the only monomer synthetized by B. sacchari. The next step was to produce biofilms from a blend of macromolecules including cheese whey, gelatin and the PHA previously obtained. Thermal and structural properties were evaluated for the obtained biofilms. X-ray diffraction showed that the addition of cheese whey in the mixture increased the crystallinity of the samples considerably, while the addition of 3-HB was very sensitive to thermomechanical degradation.