Polyhydroxyalkanoate Production by Gordonia lacunae BS2^T in Hydrolysates of Canola FinesS

Microbial polyhydroxyalkanoates (PHAs) are biodegradable biopolymers that are gaining traction as replacements for conventional petroleum-based plastics. In this study, sugar utilization, growth and polyhydroxybutyrate (PHB) and polyhdroxyvalerate (PHV) production in synthetic and real hydrolysates of Canola fines (SHCF, RHCF) by Gordonia lacunae BS2^T were evaluated: (i) in SHCF under different C:N ratios and O₂ availability, and (ii) in SHCF and RHCF (50% and 100%) under shaking v/s static conditions with limited or non-limited O₂. The bacterium was able to utilize glucose, cellobiose, arabinose, and xylose. Athough O₂ limitation reduced growth, higher measured concentrations of 3-hydroxyvalerate (3HV) were achieved under O₂ limitation, translating into slightly higher 3-hydroxybutyrate (3HB)+3HV yields (15.4 ± 2.36 %wt.wt.) than under non-O₂ limited conditions (12.4 ± 2.26 %wt.wt.). Notably, 50% RHCF was the most suitable medium for growth and PHB+PHV production, while 100% RHCF was the least suitable. The 3HV+3PV concentration (0.35 g/L), 3HV fraction (24%), and yield (15.4 %wt.wt.) in 50% RHCF were highest under static, O₂-limited conditions, corresponding with negligible sugar utilization (1.6 mg/day.100 mL⁻¹ glucose) and suggesting alternative metabolic pathways using other substrates in the RHCF for growth. Nuclear magnetic resonance results indicated that Gordonia lacunae BS2^T produces a desirable co-polymer (PHBV), paving the way for ongoing research using this bacterium.