l-Lactate oxidase-mediated removal of l-lactic acid derived from fermentation medium for the production of optically pure D-lactic acid.

Background: There has been an increasing demand for optically pure d-lactic and l-lactic acid for the production of stereocomplex-type polylactic acid. The d-lactic acid production from lignocellulosic biomass is important owing to its great abundance in nature. Corn steep liquor (CSL) is a cheap nitrogen source used for industrial fermentation, though it contains a significant amount of l-lactic acid, which decreases the optical purity of d-lactic acid produced.

Metabolic Engineering of Lactobacillus plantarum for Direct l-Lactic Acid Production From Raw Corn Starch.

Fermentative production of optically pure lactic acid (LA) has attracted great interest because of the increased demand for plant-based plastics. For cost-effective LA production, an engineered Lactobacillus plantarum NCIMB 8826 strain, which enables the production of optically pure l-LA from raw starch, is constructed. The wild-type strain produces a racemic mixture of d- and l-LA from pyruvate by the action of the respective lactate dehydrogenases (LDHs).

How lipase technology contributes to evolution of biodiesel production using multiple feedstocks.

Given the increasing interest in alternative processes for producing biodiesel, we focused on the latest screening of lipases and bioprocess design using multiple feedstocks. The implementation of lipase technology to the biodiesel industry is in the early stages. However, current research has made phenomenal advances in generating lipase variants and in engineering biodiesel production.

Production of optically pure D-lactic acid from brown rice using metabolically engineered Lactobacillus plantarum.

Simultaneous saccharification and fermentation (SSF) of D-lactic acid was performed using brown rice as both a substrate and a nutrient source. An engineered Lactobacillus plantarum NCIMB 8826 strain, in which the ʟ-lactate dehydrogenase gene was disrupted, produced 97.7 g/L D-lactic acid from 20% (w/v) brown rice without any nutrient supplementation.

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

This study focused on the process development for the d-lactic acid production from cellulosic feedstocks using the Lactobacillus plantarum mutant, genetically modified to produce optically pure d-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.

Saccharification behavior of cellulose acetate during enzymatic processing for microbial ethanol production.

This study was conducted to realize the potential application of cellulose acetate to enzymatic processing, followed by microbial ethanol fermentation. To eliminate the effect of steric hindrance of acetyl groups on the action of cellulase, cellulose acetate was subjected to deacetylation in the presence of 1N sodium hydroxide and a mixture of methanol/acetone, yielding 88.8-98.

Enzymatic production of biodiesel from waste cooking oil in a packed-bed reactor: an engineering approach to separation of hydrophilic impurities.

An engineering approach was applied to an efficient biodiesel production from waste cooking oil. In this work, an enzymatic packed-bed reactor (PBR) was integrated with a glycerol-separating system and used successfully for methanolysis, yielding a methyl ester content of 94.3% and glycerol removal of 99.

Process engineering and optimization of glycerol separation in a packed-bed reactor for enzymatic biodiesel production.

A process model for efficient glycerol separation during methanolysis in an enzymatic packed-bed reactor (PBR) was developed. A theoretical glycerol removal efficiency from the reaction mixture containing over 30% methyl esters was achieved at a high flow rate of 540 ml/h. To facilitate a stable operation of the PBR system, a batch reaction prior to continuous methanolysis was conducted using oils with different acid values and immobilized lipases pretreated with methyl esters.

Transesterification of phosphatidylcholine in sn-1 position through direct use of lipase-producing Rhizopus oryzae cells as whole-cell biocatalyst.

The enzymatic process presents an advantage of producing specified phospholipids that rarely exist in nature. In this study, we investigated the regiospecific modification of phosphatidylcholine (PC) in the sn-1 position using immobilized Rhizopus oryzae. In a reaction mixture containing egg yolk PC and exogenous lauric acid (LA) in n-hexane, lipase-producing R.

Ethanol production from biomass by repetitive solid-state fed-batch fermentation with continuous recovery of ethanol.

To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss.

Ethanol production from cellulosic materials using cellulase-expressing yeast.

We demonstrate direct ethanol fermentation from amorphous cellulose using cellulase-co-expressing yeast. Endoglucanases (EG) and cellobiohydrolases (CBH) from Trichoderma reesei, and beta-glucosidases (BGL) from Aspergillus aculeatus were integrated into genomes of the yeast strain Saccharomyces cerevisiae MT8-1. BGL was displayed on the yeast cell surface and both EG and CBH were secreted or displayed on the cell surface.

Surfactant-modified yeast whole-cell biocatalyst displaying lipase on cell surface for enzymatic production of structured lipids in organic media.

The cell surface engineering system, in which functional proteins are genetically displayed on microbial cell surfaces, has recently become a powerful tool for applied biotechnology. Here, we report on the surfactant modification of surface-displayed lipase to improve its performance for enzymatic synthesis reactions. The lipase activities of the surfactant-modified yeast displaying Rhizopus oryzae lipase (ROL) were evaluated in both aqueous and nonaqueous systems.

Marker-disruptive gene integration and URA3 recycling for multiple gene manipulation in Saccharomyces cerevisiae.

The introduction of several kinds of genes into the yeast chromosome is a powerful tool in many fields from fundamental study to industrial application. Here, we describe a general strategy for one-step gene integration and a marker recycling method. Forty base pairs of a short sequence derived from a region adjacent to the HIS3 locus were placed between cell surface displaying beta-glucosidase (BGL) and URA3 marker genes.