A natural amylopectin based quaternized polymer as a promising biopolymer for efficient dewatering of Chlorella sorokiniana NKPS02.

Microalgae are green biofactories suitable for the production of valuable bioenergy and bioproducts. Obtaining bioproducts from microalgae requires efficient microalgal biomass harvesting which is a significant bottleneck owing to the culture stability of negatively charged microalgal cells, the process is cost and energy-intensive. To overcome this, we developed a natural polymer-based quaternised amylopectin polymer by incorporating cationic reagent glycidyl trimethyl ammonium chloride (GTMAC) via etherification. Here, quaternised amylopectin appears to be a promising biopolymer for efficient dewatering of Chlorella sorokiniana NKPS02, as it resulted in >95% dewatering efficiency at the optimum dosage of 60 mg/L at ambient temperature (25 °C), physiological culture pH (∼7.8). Interestingly, the quaternised amylopectin was found to be biocompatible due to its non-interference with the lipid extraction from harvested biomass and notaffecting microalgal cell integrity. The study showed that the amylopectin-based biopolymer bridging and charge neutralization mechanism was crucial for efficient microalgal harvesting. Thus, the present endeavor exhibited that the quaternised amylopectin can be a promising biomaterial for the harvesting and sustainable valorization of microalgal biomass.