Alkane and wax ester production from lignin derived molecules

AbstractLignin has potential as a sustainable feedstock for microbial production of industrially relevant molecules. However, the required lignin depolymerization yields a heterogenic mixture of aromatic monomers that are challenging substrates for the microorganisms commonly used in industry. Here, we investigated the properties of lignin-derived molecules (LDMs), namely coumarate, ferulate, and caffeate, in the synthesis of biomass and products in a LDM-utilizing bacterial hostAcinetobacter baylyiADP1. The biosynthesis products, wax esters and alkanes, are relevant compounds for the chemical and fuel industries. InA. baylyiADP1, wax esters are produced by a native pathway, whereas alkanes are produced by a synthetic pathway introduced to the host. Using individual LDMs as substrates, the growth, product formation, and toxicity to cells were monitored with internal biosensors. Of the tested LDMs, coumarate was the most propitious in terms of product synthesis. Wax esters were produced from coumarate with a yield and titer of 40 mg /gcoumarateand 221 mg/L, whereas alkanes were produced with a yield of 62.3 μg /gcoumarateand titer of 152 μg/L. This study demonstrates the microbial preference for certain LDMs, and highlights the potential ofA. baylyiADP1 as a convenient host for LDM upgrading to value-added products.

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Wax ester production in nitrogen-rich conditions by metabolically engineered Acinetobacter baylyi ADP1

10.1101/735274 ◽

2019 ◽

Author(s):

Jin Luo ◽

Elena Efimova ◽

Pauli Losoi ◽

Ville Santala ◽

Suvi Santala

Keyword(s):

Metabolic Engineering ◽

Isocitrate Lyase ◽

Fatty Acyl ◽

Wax Esters ◽

Wax Ester ◽

High Carbon ◽

Acinetobacter Baylyi ◽

Storage Lipids ◽

Carbon Nitrogen Ratio ◽

Nitrogen Ratio

AbstractMetabolic engineering can be used as a powerful tool to redirect cell resources towards product synthesis, also in conditions that are not optimal. An example of a synthesis pathway strongly dependent on external conditions is the production of storage lipids, which typically requires high carbon/nitrogen ratio. Acinetobacter baylyi ADP1 is known for its ability to produce industrially interesting storage lipids, namely wax esters (WEs). Here, we engineered the central carbon metabolism of A. baylyi ADP1 by deletion of the gene aceA encoding for isocitrate lyase in order to allow redirection of carbon towards WEs. The production was further enhanced by overexpression of fatty acyl-CoA reductase Acr1 in the wax ester production pathway. This strategy led to 3-fold improvement in yield (0.075 g/g glucose) and 3.15-fold improvement in titer (1.82 g/L) and productivity (0.038 g/L/h) by a simple one-stage batch cultivation with glucose as carbon source. The engineered strain accumulated up to 27% WEs of cell dry weight. The titer and cellular WE content are the highest reported to date among microbes. We further showed that the engineering strategy alleviated the inherent requirement for high carbon/nitrogen ratio and demonstrated the production of wax esters using nitrogen-rich substrates including casamino acids, yeast extract and baker’s yeast hydrolysate, which support biomass production but not WE production in wild-type cells. The study demonstrates the power of metabolic engineering in overcoming natural limitations in the production of storage lipids.

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Dynamic decoupling of biomass and lipid biosynthesis by autonomously regulated switch

10.1101/337790 ◽

2018 ◽

Author(s):

Suvi Santala ◽

Elena Efimova ◽

Ville Santala

Keyword(s):

Isocitrate Lyase ◽

Glucose Dehydrogenase ◽

Lipid Synthesis ◽

Dry Weight ◽

Carbon Flow ◽

Wax Esters ◽

Wax Ester ◽

Acinetobacter Baylyi ◽

Metabolic Switch ◽

Engineered Strain

For improving the microbial production of fuels and chemicals, gene knock-outs and overexpression are routinely applied to intensify the carbon flow from substrate to product. However, their possibilities in dynamic control of the flux between the biomass and product synthesis are limited, whereas dynamic metabolic switches can be used for optimizing the distribution of carbon and resources. The production of single cell oils is especially challenging, as the synthesis is strongly regulated, competes directly with biomass, and requires defined conditions, such as nitrogen limitation. Here, we engineered a metabolic switch for redirecting carbon flow from biomass to wax ester production in Acinetobacter baylyi ADP1 using acetate as a carbon source. Isocitrate lyase, an essential enzyme for growth on acetate, was expressed under an arabinose inducible promoter. The autonomous downregulation of the expression is based on the gradual oxidation of the arabinose inducer by a glucose dehydrogenase gcd. The depletion of the inducer, occurring simultaneously to acetate consumption, switches the cells from a biomass mode to a lipid synthesis mode, enabling the efficient channelling of carbon to wax esters in a simple batch culture. In the engineered strain, the yield and titer of wax esters were improved by 3.8 and 3.1 folds, respectively, over the control strain. In addition, the engineered strain accumulated wax esters 19% of cell dry weight, being the highest reported among microbes. The study provides important insights into the dynamic engineering of the biomass-dependent synthesis pathways for the improved production of biocompounds from low-cost, sustainable substrates.

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OPPORTUNITIES FOR STRATEGIC DEVELOPMENT OF BIO-ECONOMY IN THE FOOD AND TOURISM INDUSTRY

Knowledge International Journal ◽

10.35120/kij28051681g ◽

2018 ◽

Vol 28 (5) ◽

pp. 1681-1684

Author(s):

Georgi Toskov ◽

Ana Yaneva ◽

Stanko Stankov ◽

Hafize Fidan

Keyword(s):

National Level ◽

Value Added ◽

Tourism Industry ◽

Small Companies ◽

Food Sector ◽

Strategic Development ◽

Innovation Potential ◽

Wide Range ◽

Foreign Brands ◽

Value Added Products

The European Commission defines the bioeconomy as "the production of renewable biological resources and the conversion of these resources and waste streams into value added products, such as food, feed, bio-based products and bioenergy. Its sectors and industries have strong innovation potential due to their use of a wide range of sciences, enabling and industrial technologies, along with local and implied knowledge." The Bulgarian food industry faces a lot of challenges on the local and national level, which have direct influence on the structure of the production companies. Most of the enterprises from the food sector produce under foreign brands in order to be flexible partners to the large Bulgarian retail chains. The small companies from the food sector are not able to develop as an independent competitive producer on the territory of their local markets. This kind of companies rarely has a working strategy for positioning on new markets. In order to consolidate their already built positions for long period of time, the producers are trying to optimize their operations in a short term. However, the unclear vision of the companies for the business segment does not allow them to fully develop. Tourism in Bulgaria is a significant contributor to the country's economy.

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Oxidized indium with transformable dimensions for CO2 electroreduction toward formate aided by oxygen vacancies

Sustainable Energy & Fuels ◽

10.1039/d0se00498g ◽

2020 ◽

Vol 4 (7) ◽

pp. 3726-3731

Author(s):

Fenghui Ye ◽

Jinghui Gao ◽

Yilin Chen ◽

Yunming Fang

Keyword(s):

Crucial Role ◽

Oxygen Vacancies ◽

Value Added ◽

Promising Technique ◽

Co2 Electroreduction ◽

Value Added Products

Electroreduction of CO2 into value-added products is a promising technique in which the structure of the catalyst plays a crucial role.

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β-Galactosidases from a Sequence-Based Metagenome: Cloning, Expression, Purification and Characterization

Microorganisms ◽

10.3390/microorganisms9010055 ◽

2020 ◽

Vol 9 (1) ◽

pp. 55

Author(s):

María Florencia Eberhardt ◽

José Matías Irazoqui ◽

Ariel Fernando Amadio

Keyword(s):

Bacterial Species ◽

Value Added ◽

Raw Material ◽

Activity Levels ◽

Treatment Technology ◽

Catalytic Domains ◽

Stabilization Ponds ◽

Cazy Database ◽

Genes Encoding ◽

Value Added Products

Stabilization ponds are a common treatment technology for wastewater generated by dairy industries. Large proportions of cheese whey are thrown into these ponds, creating an environmental problem because of the large volume produced and the high biological and chemical oxygen demands. Due to its composition, mainly lactose and proteins, it can be considered as a raw material for value-added products, through physicochemical or enzymatic treatments. β-Galactosidases (EC 3.2.1.23) are lactose modifying enzymes that can transform lactose in free monomers, glucose and galactose, or galactooligosacharides. Here, the identification of novel genes encoding β-galactosidases, identified via whole-genome shotgun sequencing of the metagenome of dairy industries stabilization ponds is reported. The genes were selected based on the conservation of catalytic domains, comparing against the CAZy database, and focusing on families with β-galactosidases activity (GH1, GH2 and GH42). A total of 394 candidate genes were found, all belonging to bacterial species. From these candidates, 12 were selected to be cloned and expressed. A total of six enzymes were expressed, and five cleaved efficiently ortho-nitrophenyl-β-galactoside and lactose. The activity levels of one of these novel β-galactosidase was higher than other enzymes reported from functional metagenomics screening and higher than the only enzyme reported from sequence-based metagenomics. A group of novel mesophilic β-galactosidases from diary stabilization ponds’ metagenomes was successfully identified, cloned and expressed. These novel enzymes provide alternatives for the production of value-added products from dairy industries’ by-products.

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Milk Fat Globule Membrane Proteome and Micronutrients in the Milk Lipid Fraction: Insights into Milk Bioactive Compounds

Dairy ◽

10.3390/dairy2020018 ◽

2021 ◽

Vol 2 (2) ◽

pp. 202-217

Author(s):

Michele Manoni ◽

Donata Cattaneo ◽

Sharon Mazzoleni ◽

Carlotta Giromini ◽

Antonella Baldi ◽

...

Keyword(s):

Milk Fat ◽

Lipid Fraction ◽

Value Added ◽

Milk Lipid ◽

Milk Fat Globule Membrane ◽

Fat Globules ◽

Milk Fat Globules ◽

Milk Fat Globule ◽

Fat Globule ◽

Value Added Products

Milk lipids are composed of milk fat globules (MFGs) surrounded by the milk fat globule membrane (MFGM). MFGM protects MFGs from coalescence and enzymatic degradation. The milk lipid fraction is a “natural solvent” for macronutrients such as phospholipids, proteins and cholesterol, and micronutrients such as minerals and vitamins. The research focused largely on the polar lipids of MFGM, given their wide bioactive properties. In this review we discussed (i) the composition of MFGM proteome and its variations among species and phases of lactation and (ii) the micronutrient content of human and cow’s milk lipid fraction. The major MFGM proteins are shared among species, but the molecular function and protein expression of MFGM proteins vary among species and phases of lactation. The main minerals in the milk lipid fraction are iron, zinc, copper and calcium, whereas the major vitamins are vitamin A, β-carotene, riboflavin and α-tocopherol. The update and the combination of this knowledge could lead to the exploitation of the MFGM proteome and the milk lipid fraction at nutritional, biological or technological levels. An example is the design of innovative and value-added products, such as MFGM-supplemented infant formulas.

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