Replacement of a Metabolic Pathway for Large-Scale Production of Lactic Acid from Engineered Yeasts

ABSTRACT Interest in the production of l-(+)-lactic acid is presently growing in relation to its applications in the synthesis of biodegradable polymer materials. With the aim of obtaining efficient production and high productivity, we introduced the bovinel-lactate dehydrogenase gene (LDH) into a wild-type Kluyveromyces lactis yeast strain. The observed lactic acid production was not satisfactory due to the continued coproduction of ethanol. A further restructuring of the cellular metabolism was obtained by introducing the LDH gene into aK. lactis strain in which the unique pyruvate decarboxylase gene had been deleted. With this modified strain, in which lactic fermentation substituted completely for the pathway leading to the production of ethanol, we obtained concentrations, productivities, and yields of lactic acid as high as 109 g liter−1, 0.91 g liter−1 h−1, and 1.19 mol per mole of glucose consumed, respectively. The organic acid was also produced at pH levels lower than those usual for bacterial processes.

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Biotechnological valorization of agro industrial and household wastes for lactic acid production

Revista Colombiana de Biotecnología ◽

10.15446/rev.colomb.biote.v21n1.69284 ◽

2019 ◽

Vol 21 (1) ◽

pp. 113-127 ◽

Cited By ~ 1

Author(s):

Juliana Romo-Buchelly ◽

María Rodríguez-Torres ◽

Fernando Orozco-Sánchez

Keyword(s):

Lactic Acid ◽

Large Scale ◽

Lactic Acid Production ◽

Scale Production ◽

Advantages And Disadvantages ◽

Large Scale Production ◽

Different Types ◽

High Transformation ◽

Transformation Potential ◽

The Cost

Lactic acid (LA) is an organic compound used in several industries, such as food, textile, chemical, and pharmaceutical. The global interest in this product is due to its use for the synthesis of numerous chemical compounds, including polylactic acid, a biode-gradable thermoplastic and substitute for petroleum-derived plastics. An in-depth overview of the use of industrial and household wastes as inexpensive substrates in order to reduce the cost of LA production is presented. A review is carried out of the biotech-nological aspects that must be taken into account when using some wastes with high transformation potential to produce LA in a submerged culture, as well recommendations for their use. The advantages and disadvantages of different types of treatments used for the transformation of waste into suitable substrates are considered. Several methods of fermentation, as well as genetic strategies for increasing the production, are summarized and compared. It is expected that in a few years there will be many ad-vances in these areas that will allow greater large-scale production of LA using agroindustrial or household wastes, with potential positive economic and environmental impact in some regions of the planet.

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Efficient Production of l-Ribose with a Recombinant Escherichia coli Biocatalyst

Applied and Environmental Microbiology ◽

10.1128/aem.02768-07 ◽

2008 ◽

Vol 74 (10) ◽

pp. 2967-2975 ◽

Cited By ~ 30

Author(s):

Ryan D. Woodyer ◽

Nathan J. Wymer ◽

F. Michael Racine ◽

Shama N. Khan ◽

Badal C. Saha

Keyword(s):

Escherichia Coli ◽

Large Scale ◽

Active Form ◽

Apium Graveolens ◽

Efficient Production ◽

Scale Production ◽

Gene Encoding ◽

Large Scale Production ◽

One Step ◽

Rare Sugars

ABSTRACT A new synthetic platform with potential for the production of several rare sugars, with l-ribose as the model target, is described. The gene encoding the unique NAD-dependent mannitol-1-dehydrogenase (MDH) from Apium graveolens (garden celery) was synthetically constructed for optimal expression in Escherichia coli. This MDH enzyme catalyzes the interconversion of several polyols and their l-sugar counterparts, including the conversion of ribitol to l-ribose. Expression of recombinant MDH in the active form was successfully achieved, and one-step purification was demonstrated. Using the created recombinant E. coli strain as a whole-cell catalyst, the synthetic utility was demonstrated for production of l-ribose, and the system was improved using shaken flask experiments. It was determined that addition of 50 to 500 μM ZnCl2 and addition of 5 g/liter glycerol both improved production. The final levels of conversion achieved were >70% at a concentration of 40 g/liter and >50% at a concentration of 100 g/liter. The best conditions determined were then scaled up to a 1-liter fermentation that resulted in 55% conversion of 100 g/liter ribitol in 72 h, for a volumetric productivity of 17.4 g liter−1 day−1. This system represents a significantly improved method for the large-scale production of l-ribose.

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Efficient Homolactic Fermentation byKluyveromyces lactis Strains Defective in Pyruvate Utilization and Transformed with the HeterologousLDH Gene

Applied and Environmental Microbiology ◽

10.1128/aem.67.12.5621-5625.2001 ◽

2001 ◽

Vol 67 (12) ◽

pp. 5621-5625 ◽

Cited By ~ 56

Author(s):

Michele M. Bianchi ◽

Luca Brambilla ◽

Francesca Protani ◽

Chi-Li Liu ◽

Jefferson Lievense ◽

...

Keyword(s):

Lactic Acid ◽

Lactate Dehydrogenase ◽

Fermentation Broth ◽

Kluyveromyces Lactis ◽

Large Fraction ◽

Lactic Acid Production ◽

Pyruvate Decarboxylase ◽

High Yield ◽

Theoretical Yield ◽

Ldh Activity

ABSTRACT A high yield of lactic acid per gram of glucose consumed and the absence of additional metabolites in the fermentation broth are two important goals of lactic acid production by microrganisms. Both purposes have been previously approached by using aKluyveromyces lactis yeast strain lacking the single pyruvate decarboxylase gene (KlPDC1) and transformed with the heterologous lactate dehydrogenase gene (LDH). The LDH gene was placed under the control theKlPDC1 promoter, which has allowed very high levels of lactate dehydrogenase (LDH) activity, due to the absence of autoregulation by KlPdc1p. The maximal yield obtained was 0.58 g g−1, suggesting that a large fraction of the glucose consumed was not converted into pyruvate. In a different attempt to redirect pyruvate flux toward homolactic fermentation, we usedK. lactis LDH transformant strains deleted of the pyruvate dehydrogenase (PDH) E1α subunit gene. A great process improvement was obtained by the use of producing strains lacking both PDH and pyruvate decarboxylase activities, which showed yield levels of as high as 0.85 g g−1 (maximum theoretical yield, 1 g g−1), and with high LDH activity.

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Production of isomelezitose from sucrose by engineered glucansucrases

Amylase ◽

10.1515/amylase-2017-0008 ◽

2017 ◽

Vol 1 (1) ◽

Cited By ~ 3

Author(s):

Gregory L. Côté ◽

Christopher A. Dunlap ◽

Karl E. Vermillion ◽

Christopher D. Skory

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Biomedical Applications ◽

Large Scale ◽

Single Point ◽

Single Point Mutation ◽

Scale Production ◽

Acceptor Substrate ◽

Large Scale Production ◽

High Yields

AbstractCertain lactic acid bacteria produce glycosyltransferases known as glucansucrases, which synthesize α-D-glucans via glucosyl transfer from sucrose. We recently reported on the formation of the unusual trisaccharide isomelezitose in low yields by a variety of glucansucrases. Isomelezitose is a rare non-reducing trisaccharide, with the structure α-d-glucopyranosyl- (1→6)-β-d-fructofuranosyl-(2↔1)-α-d-glucopyranoside. In this work, we describe the synthesis of isomelezitose in high yields by variants of glucansucrases engineered to contain a single point mutation at a key leucine residue involved in acceptor substrate binding. Some variants produce isomelezitose in yields up to 57%. This method is amenable to large-scale production of isomelezitose for food, industrial and biomedical applications.

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Tolerance engineering in Deinococcus geothermalis by heterologous efflux pumps

Scientific Reports ◽

10.1038/s41598-021-83339-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Erika Boulant ◽

Emmanuelle Cambon ◽

Julia Vergalli ◽

Rémi Bernard ◽

Fabienne Neulat-Ripoll ◽

...

Keyword(s):

Large Scale ◽

Efflux Pumps ◽

Toxic Effects ◽

Efficient Production ◽

Scale Production ◽

Gene Encoding ◽

Large Scale Production ◽

Deinococcus Geothermalis ◽

Genes Encoding ◽

Susceptibility Tests

AbstractProducing industrially significant compounds with more environmentally friendly represents a challenging task. The large-scale production of an exogenous molecule in a host microfactory can quickly cause toxic effects, forcing the cell to inhibit production to survive. The key point to counter these toxic effects is to promote a gain of tolerance in the host, for instance, by inducing a constant flux of the neo-synthetized compound out of the producing cells. Efflux pumps are membrane proteins that constitute the most powerful mechanism to release molecules out of cells. We propose here a new biological model, Deinococcus geothermalis, organism known for its ability to survive hostile environment; with the aim of coupling the promising industrial potential of this species with that of heterologous efflux pumps to promote engineering tolerance. In this study, clones of D. geothermalis containing various genes encoding chromosomal heterologous efflux pumps were generated. Resistant recombinants were selected using antibiotic susceptibility tests to screen promising candidates. We then developed a method to determine the efflux efficiency of the best candidate, which contains the gene encoding the MdfA of Salmonella enterica serovar Choleraesuis. We observe 1.6 times more compound in the external medium of the hit recombinant than that of the WT at early incubation time. The data presented here will contribute to better understanding of the parameters required for efficient production in D. geothermalis.

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Effects of Radishes, Apples, and Pears on the Lactic Acid Bacteria and Nutritional and Functional Qualities of Flavored Soy Sauce

Foods ◽

10.3390/foods9111562 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1562

Author(s):

Ashutosh Bahuguna ◽

Il Guk Jo ◽

Jong Suk Lee ◽

Myunghee Kim

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Xanthine Oxidase ◽

Large Scale ◽

Antioxidant Activities ◽

Soy Sauce ◽

Scale Production ◽

Large Scale Production ◽

Total Free Amino Acids

Producers of soy sauce are constantly making efforts to improve the sensory quality and nutritional value of their products. In this study, radishes, apples, and pears were used to prepare a distinctly flavored soy sauce, and the lactic acid bacteria, volatile compound content, and nutritional and functional qualities of the product were compared with two commercial flavored soy sauce products. Comparable physiochemical properties, antioxidant activities (in vitro and cellular), and higher prevalence of lactic acid bacteria (7.74 ± 0.55 log CFU mL−1) were observed in the prepared flavored soy sauce than in commercial flavored soy sauce. The comprehensive enzyme activity profile of the isolated lactic acid bacteria, Tetragenococcus halophilus (NCBI GenBank Accession no. MN270899), revealed the absence of any harmful enzymes such as β-glucuronidase. Moreover, the cell-free extract of T. halophilus showed xanthine oxidase inhibitory activity (half maximal inhibitory concentration (IC50) = 0.79 mg mL−1), suggesting that the product possessed functionality against xanthine oxidase-induced oxidative stress. Additionally, the prepared flavored soy sauce had higher amounts of total free amino acids (48.68 mg mL−1) and organic acids (7.77 mg mL−1). These results suggest that radishes, apples, and pears at a defined ratio are suitable for the large scale production of a flavored soy sauce with improved nutritional and functional qualities.

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Production of 10-methyl branched fatty acids in yeast

Biotechnology for Biofuels ◽

10.1186/s13068-020-01863-0 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Hannah G. Blitzblau ◽

Andrew L. Consiglio ◽

Paulo Teixeira ◽

Donald V. Crabtree ◽

Shuyan Chen ◽

...

Keyword(s):

Fatty Acids ◽

High Performance ◽

Large Scale ◽

Unsaturated Fatty Acids ◽

Acyl Chain ◽

Efficient Production ◽

Scale Production ◽

Branched Fatty Acids ◽

Large Scale Production ◽

Methyl Branched Fatty Acids

Abstract Background Despite the environmental value of biobased lubricants, they account for less than 2% of global lubricant use due to poor thermo-oxidative stability arising from the presence of unsaturated double bonds. Methyl branched fatty acids (BFAs), particularly those with branching near the acyl-chain mid-point, are a high-performance alternative to existing vegetable oils because of their low melting temperature and full saturation. Results We cloned and characterized two pathways to produce 10-methyl BFAs isolated from actinomycetes and γ-proteobacteria. In the two-step bfa pathway of actinomycetes, BfaB methylates Δ9 unsaturated fatty acids to form 10-methylene BFAs, and subsequently, BfaA reduces the double bond to produce a fully saturated 10-methyl branched fatty acid. A BfaA-B fusion enzyme increased the conversion efficiency of 10-methyl BFAs. The ten-methyl palmitate production (tmp) pathway of γ-proteobacteria produces a 10-methylene intermediate, but the TmpA putative reductase was not active in E. coli or yeast. Comparison of BfaB and TmpB activities revealed a range of substrate specificities from C14-C20 fatty acids unsaturated at the Δ9, Δ10 or Δ11 position. We demonstrated efficient production of 10-methylene and 10-methyl BFAs in S. cerevisiae by secretion of free fatty acids and in Y. lipolytica as triacylglycerides, which accumulated to levels more than 35% of total cellular fatty acids. Conclusions We report here the characterization of a set of enzymes that can produce position-specific methylene and methyl branched fatty acids. Yeast expression of bfa enzymes can provide a platform for the large-scale production of branched fatty acids suitable for industrial and consumer applications.

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Studies and Practice of Geometrical Test Procedures & Reconditioning of CNC Lathe Machine Tool

Journal of Physics Conference Series ◽

10.1088/1742-6596/2070/1/012228 ◽

2021 ◽

Vol 2070 (1) ◽

pp. 012228

Author(s):

Jerin Beno ◽

M VeeraBhadra Rao ◽

Sunil Kumar Das

Keyword(s):

Machine Tool ◽

Large Scale ◽

Scale Production ◽

Test Procedures ◽

High Productivity ◽

Large Scale Production ◽

Cnc Lathe ◽

Lathe Machine ◽

Manufacturing Technologies ◽

Indian Industries

Abstract Machining Centres have been major production units for many decades with desired levels of accuracy, economy in costs of production and ease of control. Though new disruptive technologies such as rapid manufacturing, near net shape manufacturing technologies are replacing these machining units, still small and medium Indian Industries go with the conventional ways of large-scale production using conventional and classical machining approaches. With huge setups in place, such machines with high productivity demands, require stringent parts alignment tests frequently from time to time, referred to as Geometrical or Alignment tests to enable accurate finishing and machining of parts and smooth and uninterrupted production. This paper puts forth some basic Geometrical Tests performed on SB CNC 60 Lathe Machine Tool unit, identifying major deviations measurements and reconditioning the machine parts. The main objective of running such tests is to prevent breakdown of the machine and ensure safety working when handling older and heavier conventional machines.

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Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.13.141 ◽

2017 ◽

Vol 13 ◽

pp. 1439-1445 ◽

Cited By ~ 11

Author(s):

Ana Franco ◽

Sudipta De ◽

Alina M Balu ◽

Araceli Garcia ◽

Rafael Luque

Keyword(s):

Graphene Oxide ◽

Transition Metal ◽

Large Scale ◽

Metal Catalysts ◽

Transition Metal Catalysts ◽

Efficient Production ◽

Scale Production ◽

Supported Metal Catalysts ◽

Co Catalysts ◽

Large Scale Production

Vanillin is one of the most commonly used natural products, which can also be produced from lignin-derived feedstocks. The chemical synthesis of vanillin is well-established in large-scale production from petrochemical-based starting materials. To overcome this problem, lignin-derived monomers (such as eugenol, isoeugenol, ferulic acid etc.) have been effectively used in the past few years. However, selective and efficient production of vanillin from these feedstocks still remains an issue to replace the existing process. In this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H2O2 as oxidizing agent. Fe catalysts were more selective as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol.

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Cereal- and Fruit-Based Ethiopian Traditional Fermented Alcoholic Beverages

Foods ◽

10.3390/foods9121781 ◽

2020 ◽

Vol 9 (12) ◽

pp. 1781

Author(s):

Eskindir Getachew Fentie ◽

Shimelis Admassu Emire ◽

Hundessa Dessalegn Demsash ◽

Debebe Worku Dadi ◽

Jae-Ho Shin

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Physicochemical Properties ◽

Indigenous Knowledge ◽

Large Scale ◽

Alcoholic Beverages ◽

Scale Production ◽

Microbial Dynamics ◽

Nutritional Values ◽

Large Scale Production

Traditional fermented alcoholic beverages are drinks produced locally using indigenous knowledge, and consumed near the vicinity of production. In Ethiopia, preparation and consumption of cereal- and fruit-based traditional fermented alcoholic beverages is very common. Tella, Borde, Shamita, Korefe, Cheka, Tej, Ogol, Booka, and Keribo are among the popular alcoholic beverages in the country. These beverages have equal market share with commercially produced alcoholic beverages. Fermentation of Ethiopian alcoholic beverages is spontaneous, natural and uncontrolled. Consequently, achieving consistent quality in the final product is the major challenge. Yeasts and lactic acid bacteria are the predominate microorganisms encountered during the fermentation of these traditional alcoholic beverages. In this paper, we undertake a review in order to elucidate the physicochemical properties, indigenous processing methods, nutritional values, functional properties, fermenting microorganisms and fermentation microbial dynamics of Ethiopian traditional alcoholic beverages. Further research will be needed in order to move these traditional beverages into large-scale production.

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