Improvement of Polymer Grade L-Lactic Acid Production Using Lactobacillus rhamnosus SCJ9 from Low-Grade Cassava Chips by Simultaneous Saccharification and Fermentation

Abstract

The present study aims to examine the process for L-lactic acid production from low-grade cassava chips (LGC) using a two-step fermentation approach (TSF) and simultaneous saccharification and fermentation (SSF) by proficient, newly isolated Lactobacillus rhamnosus strain SCJ9. The optimized medium composition revealed by response surface methodology for TSF was 166 g/L LGC hydrolysate and 20 g/L yeast extract (YE), while other medium components were fixed (g/L) as follows: tween80 (2.0), (NH4)2HPO4 (2.0), CH3COONa∙3H2O (6.0), (NH4)2HC6H5O7 (2.0), MgSO4∙7H2O (0.5), and MnSO4∙H2O (0.3). Based on the optimization conditions, the maximum experimental L-lactic acid of 134.6 g/L was achieved at 60 h fermentation time with a production efficiency of 89.73%, 0.95 g/g yield and 2.24 g/L/h productivity. In contrast, L-lactic acid production by SSF under optimized concentrations of thermostable-α-amylase (AA) and glucoamylase (GA) gave maximum L-lactic acid of 125.79 g/L at only 36 h fermentation time which calculated to the production efficiency, yield and productivity of 83.86%, 0.93 g/g and 3.49 g/L/h, respectively. The L-lactic acid production obtained from SSF was significantly improved when compared to TSF based on lower enzyme loading usage, shorter hydrolysis time and increase in production efficiency and productivity. Furthermore, there were no significant differences in the production by SSF between experiments conducted in laboratory bottle and 10-L fermenter. The results indicated the success of up-scaling for L-lactic acid production by SSF which could be developed for a further pilot-scale production of L-lactic acid.

Bio-Characterization and Liquid Chromatography–Mass Spectrometry Analysis of Exopolysaccharides in Biofilm-Producing Cyanobacteria Isolated from Soil Crust: Exploring the Potential of Microalgal Biomolecules

“…EPSs with a positive charge decreased the Kaolin’s negative electrical charge, leading to flocculates. It was observed that EPSd from the biological soil crust induced the flocculation of fine kaolin particles and enhanced the flocculating process by increasing the concentration of uronic acid in the EPS [ 47 , 48 ]. In addition, the flocculation activity of EPSs is due to their natural anionic charge.…”

A Thermotolerant Yeast Cyberlindnera rhodanensis DK Isolated from Laphet-so Capable of Extracellular Thermostable β-Glucosidase Production

“…The Plackett-Burman design is a valuable statistical design that is particularly useful when dealing with a large number of potential factors that may influence the targeted product yield. Based on the employment of linear regression analysis, this design helps to identify and prioritize the significant factors affecting the responses of interested products while filtering out irrelevant factors [72]. However, the PBD presents certain limitations.…”

Improvement of Enantiomeric l-Lactic Acid Production from Mixed Hexose-Pentose Sugars by Coculture of Enterococcus mundtii WX1 and Lactobacillus rhamnosus SCJ9

“…2.6. L-LA Production from Mixed Glucose and Xylose by Coculture Fermentation E. mundtii WX1 was designed for coculture fermentation when combined with Lactobacillus rhamnosus SCJ9, a highly active homofermentative LAB capable of producing L-LA from only glucose [21]. The mixed sugar of glucose and xylose in a ratio of 6:4 was selected as a model for LA fermentation.…”