Production of d-lactic acid from hardwood pulp by mechanical milling followed by simultaneous saccharification and fermentation using metabolically engineered Lactobacillus plantarum. (July 2015)

• Record Type: Journal Article
• Authors: Hama, Shinji; Mizuno, Shino; Kihara, Maki; Tanaka, Tsutomu; Ogino, Chiaki; Noda, Hideo; Kondo, Akihiko
• Is Part Of: Bioresource technology. Volume 187(2015)
• Page Start: 167
• Page End: 172
• Publication Date: 2015-07
• Subjects: d-Lactic acid -- Kraft pulp -- Pretreatment -- Ball milling; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2015.03.106
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: Process for high-titerd -lactic acid production from cellulosic feedstocks. Simultaneous saccharification and fermentation is suggested to improve the process. To improve saccharification of high-load pulp, high-impact pulverization is applied. A combined process for increasing the lactic acid titer above 100 g/L. Abstract: This study focused on the process development for thed -lactic acid production from cellulosic feedstocks using the Lactobacillus plantarum mutant, genetically modified to produce optically pured -lactic acid from both glucose and xylose. The simultaneous saccharification and fermentation (SSF) using delignified hardwood pulp (5–15% loads) resulted in the lactic acid titers of 55.2–84.6 g/L after 72 h and increased productivities of 1.77–2.61 g/L/h. To facilitate the enzymatic saccharification of high-load pulp at a fermentation temperature, short-term (⩽10 min) pulverization of pulp was conducted, leading to a significantly improved saccharification with the suppressed formation of formic acid by-product. The short-term milling followed by SSF resulted in a lactic acid titer of 102.3 g/L, an optical purity of 99.2%, and a yield of 0.879 g/g-sugars without fed-batch process control. Therefore, the process presented here shows promise for the production of high-titerd -lactic acid using the L. plantarum mutant.