D-lactic acid production from hydrothermally pretreated, alkali delignified and enzymatically saccharified rockrose with the metabolic engineered Escherichia coli strain JU15

Rockrose lignocellulosic residues (RR) were selectively fractionated for hemicellulose separation using autohydrolysis, followed by an alkaline treatment to solubilize the lignin. The cellulose-enriched solids used study effect of solid loading (SL: 2–10%) and enzyme dosage (ED: 6.34–23.66 FPU/g dry biomass) on saccharification a Doehlert experimental design, fermentation with metabolic engineered Escherichia coli strain JU15 produce D-lactic acid (DLA). Pretreatment increased glucan content enzymatic digestibility up 84%. A significant positive SL ED was found glucose production, but negatively impacted yield. DLA concentrations productivity varied from 8.85 32.98 g/L 1.11 2.17 g/(Lh), respectively. Overall process efficiency strongly depended yield 33 71%. These results indicate that sequential delignification, RR may be potential relevant strategy production in biorefinery framework.