Carbon dioxide and poultry waste utilization for production of polyhydroxyalkanoate biopolymers by Nostoc muscorum Agardh: a sustainable approach

The new paradigm is to view wastes as resources for sustainable development. In this regard, the feasibility of poultry waste and CO2 utilization for cultivation of a filamentous nitrogen-fixing cyanobacterium, Nostoc muscorum Agardh, was investigated for production polyhydroxyalkanoates, the biodegradable polymers. This cyanobacterium showed profound rise in biomass yield with up to 10 % CO2 supply in airstream with an aeration rate of 0.1 vvm. Maximum biomass yield of 1.12 g L-1 was recorded for 8 days incubation period, thus demonstrating a CO2 biofixation rate of 0.263 g L-1 day(-1) at 10 % (v/v) CO2-enriched air. Poultry litter (PL) supplementation also had a positive impact on the biomass yield. The nutrient removal efficiency of N. muscorum was reflected in the significant reduction in nutrient load of PL over the experimental period. A maximum poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) [P(3HB-co-3HV)] copolymer yield of 774 mg L-1 (65 % of dry cell wt.), the value almost 11-fold higher than the control, was recorded in 10 g L-1 PL-supplemented cultures with 10 % CO2 supply under the optimized condition, thus demonstrating that N. muscorum has good potential for CO2 biomitigation and poultry waste remediation while simultaneously producing eco-friendly polymers.