Production of optical pure L-lactic acid from Cabernet Sauvignon grape pomace by engineered Lactiplantibacillus plantarum

Cabernet Sauvignon grape pomace contains carbohydrates and various amino acids that could be used as substrates for lactic acid (LA) production. In this study, a mutant strain of L. plantarum with deletion the D-lactate synthesis gene was developed to produce optical pure L-LA from pomace. The highest purity produced by 99.61%. direct bioconversion raw substrate showed low LA yield. Several pretreatment methods were applied improve yield, including ball milling, hydrothermal, dilute pretreatment, alkaline combined wet mechanical pretreatment. Due efficient delignification, achieved yield 96.26% at 15% solid loading, corresponding concentration volumetric productivity 18.45 g/L 2.30 g/L·h, respectively.