Lactobacillus casei as a biocatalyst for biofuel production

Abstract

Microbial fermentation of sugars from plant biomass to alcohols represents an alternative to petroleum-based fuels. The optimal biocatalyst for such fermentations needs to overcome hurdles such as high concentrations of alcohols and toxic compounds. Lactic acid bacteria, especially lactobacilli, have high innate alcohol tolerance and are remarkably adaptive to harsh environments. This study assessed the potential of five Lactobacillus casei strains as biocatalysts for alcohol production. L. casei 12A was selected based upon its innate alcohol tolerance, high transformation efficiency and ability to utilize plant-derived carbohydrates. A 12A derivative engineered to produce ethanol (L. casei E1) was compared to two other bacterial biocatalysts. Maximal growth rate, maximal optical density and ethanol production were determined under conditions similar to those present during alcohol production from lignocellulosic feedstocks. L. casei E1 exhibited higher innate alcohol tolerance, better growth in the presence of corn stover hydrolysate stressors, and resulted in higher ethanol yields.

CRISPR-Cas9 D10A Nickase-Assisted Genome Editing in Lactobacillus casei

“…L actobacillus casei, one of the species of lactic acid bacteria (LAB), has been used for centuries as a health-promoting microbe in fermented food to decrease inflammation, regulate the intestinal microenvironment, and reduce stress-associated abdominal dysfunction in healthy subjects exposed to stressful situations (1)(2)(3). As a robust organism, L. casei can adapt to a wide range of harsh environments, e.g., it has a high tolerance to alcohol (4). This characteristic increases its potential application and makes it an attractive candidate for use in biofuel and pharmaceutical production, in addition to traditional food fermentation (5)(6)(7).…”

Effects of carbon concentration, oxygen, and controlled pH on the engineering strain Lactiplantibacillus casei E1 in the production of bioethanol from sugarcane molasses

“…The engineered L. casei E1, a derivative of wild strain L. casei 12A (GenBank: CP006690.1) lacking ldh1, was constructed using the procedure described by Broadbent et al (2003). Briefly, a synthetic production of ethanol (PET) cassette encoding the Zymomonas mobilis pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADHII) genes under the control of the native L. casei 12A phosphoglycerate mutase (pgm) promoter (L. casei 12A Δldh1::Ppgm-PET) was assembled and codon-optimized using Java Codon Adaptation Tool and inserted into the 12A ldh1 locus (Vinay-Lara et al 2016).…”

“…The effects of oxygen on products of L. casei strain using food-wastes substrate had be genetically verified and analyzed in detail (Ricciardi et al 2019). L. casei synthesizes various organic acids such as pyruvate, lactic acid, acetic acid, and succinic acid (Vinay-Lara et al 2016). Fermentation progresses, organic acids that can increase the acidity of fermentation liquid gradually accumulate.…”

“…In this study, one strain L. casei E1, which was engineered from wild strain L. casei 12A to produce ethanol instead of lactate as its major end-product from carbohydrates (Vinay-Lara et al 2016), was selected to explore the effects of environmental factors on the metabolisms. Using sugarcane molasses solution as medium, the living cell number, the carbohydrates utilization, and product synthesis abilities of the strain under different conditions were analyzed.…”

Natural diversity of lactococci in γ-aminobutyric acid (GABA) production and genetic and phenotypic determinants

“…Lactic acid bacteria (LAB) are widely used in the food industry (cheese, buttermilk, sour cream, yogurt) as acidifiers (converting sugars into lactic acid) [1], food thickeners [2] and as bacteriocin producers [3,4]. They also contribute to the flavor of dairy products [5] and interest in their potential use as cell factories for the chemical industry (biofuels, solvents, bio-based plastics) has grown in recent years [6][7][8][9]. Another attractive feature of LAB is their ability to produce a range of molecules with healthcare applications such as bioactive peptides, vitamins, hyaluronic acid and γ-aminobutyric acid (GABA) [10][11][12].…”