Statistical optimization of black liquor-containing media for growth and lactic acid production by Paenibacillus glucanolyticus SLM1

Abstract

Paenibacillus glucanolyticus SLM1 is a bacterial species isolated from black liquor that can metabolize lignocellulosic components. To improve P. glucanolyticus SLM1 growth and metabolism of lignocellulose components contained in black liquor, a Plackett-Burman and Central Composite Design (CCD) with Response Surface Methodology (RSM) approach was used to optimize media for aerobic growth and anaerobic organic acid production. Generation time reduced from 4.1 h to 2.1 h in optimized media. Biomass accumulation in optimized media was 3.6 ± 0.40 g/L compared to 1.8 ± 0.70 g/L in unoptimized media. Anaerobic formulation of optimized media showed increased production of lactic acid at 0.26 ± 0.05 g/L. Vanillic acid was produced in small amounts ranging from 21 ± 0.30 mg/L to 35 ± 0.03 mg/L from media used in the CCD experiments. Optimization results indicate that increased rich media components, salts, and phosphate content can reduce inhibition of growth by black liquor.