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

Abstract

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.