Sequential extraction of cyanophycin granule polypeptide and lipids from algal-bacterial consortia: Simultaneous recovery of biopolymer and fat acids.

The algal-bacterial consortia have garnered significant attention for its efficacy in pollutant removal and the recovery of value-added chemicals. However, the extraction of diverse chemicals (e.g. biomacromolecules, fatty acids) from algal-bacterial biomass remain underexplored. This study investigated a method for the successive separation of lipids and high value biopolymer cyanophycin granule polypeptide (CGP) from algal-bacterial biomass, alongside the purification of CGP and the reusability of the extractant via membrane filtration. A maximum lipids yield of 32.7 wt% was achieved with a chloroform-methanol dosage of 200 mL/g dry biomass and 60 min stirring at 25 °C. The maximum CGP yield reached 7.9 wt% under 1 M HCl, a liquid-to-solid ratio of 100 mL/g dry biomass, and 60 min heating at 80 °C with stirring. Notably, the sequential extraction of lipids followed by CGP did not impact the CGP yield. Furthermore, the sequential extraction process showed that multistage membrane filtration (30 and 10 kDa) effectively separated CGP from the extractant, achieving a 98 % recovery of CGP while significantly reducing the content of inorganic elements. The separated HCl extractant maintained its effectiveness after three cycles of CGP extraction. This study introduces a novel strategy for the sequential extraction and purification of lipids and CGP, advancing the efficient recovery and utilization of bioresources.