scholarly journals Convergent Evolution of a Promiscuous 3-Hydroxypropionyl-CoA Dehydratase/Crotonyl-CoA Hydratase in Crenarchaeota and Thaumarchaeota

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Li Liu ◽  
Philip C. Brown ◽  
Martin Könneke ◽  
Harald Huber ◽  
Simone König ◽  
...  
Keyword(s):  
Convergent Evolution ◽  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Value Added ◽  
Striking Similarity ◽  
Heterologous Host ◽  
Content Type ◽  
Metallosphaera Sedula ◽  
Geothermal Environments ◽  
Value Added Products

ABSTRACT The autotrophic 3-hydroxypropionate/4-hydroxybutyrate (HP/HB) cycle functions in thermoacidophilic, (micro)aerobic, hydrogen-oxidizing Crenarchaeota of the order Sulfolobales as well as in mesophilic, aerobic, ammonia-oxidizing Thaumarchaeota. Notably, the HP/HB cycle evolved independently in these two archaeal lineages, and crenarchaeal and thaumarchaeal versions differ regarding their enzyme properties and phylogeny. These differences result in altered energetic efficiencies between the variants. Compared to the crenarchaeal HP/HB cycle, the thaumarchaeal variant saves two ATP equivalents per turn, rendering it the most energy-efficient aerobic pathway for carbon fixation. Characteristically, the HP/HB cycle includes two enoyl coenzyme A (CoA) hydratase reactions: the 3-hydroxypropionyl-CoA dehydratase reaction and the crotonyl-CoA hydratase reaction. In this study, we show that both reactions are catalyzed in the aforementioned archaeal groups by a promiscuous 3-hydroxypropionyl-CoA dehydratase/crotonyl-CoA hydratase (Msed_2001 in crenarchaeon Metallosphaera sedula and Nmar_1308 in thaumarchaeon Nitrosopumilus maritimus). Although these two enzymes are homologous, they are closely related to bacterial enoyl-CoA hydratases and were retrieved independently from the same enzyme pool by the ancestors of Crenarchaeota and Thaumarchaeota, despite the existence of multiple alternatives. This striking similarity in the emergence of enzymes involved in inorganic carbon fixation from two independently evolved pathways highlights that convergent evolution of autotrophy could be much more widespread than anticipated. IMPORTANCE Inorganic carbon fixation is the most important biosynthetic process on Earth and the oldest type of metabolism. The autotrophic HP/HB cycle functions in Crenarchaeota of the order Sulfolobales and in ammonia-oxidizing Archaea of the phylum Thaumarchaeota that are highly abundant in marine, terrestrial, and geothermal environments. Bioinformatic prediction of the autotrophic potential of microorganisms or microbial communities requires identification of enzymes involved in autotrophy. However, many microorganisms possess several isoenzymes that may potentially catalyze the reactions of the cycle. Here, we studied the enzymes catalyzing 3-hydroxypropionyl-CoA dehydration and crotonyl-CoA hydration in Nitrosopumilus maritimus (Thaumarchaeota) as well as in Metallosphaera sedula (Crenarchaeota). We showed that both reactions were catalyzed by homologous promiscuous enzymes, which evolved independently from each other from their bacterial homologs. Furthermore, the HP/HB cycle is of applied value, and knowledge of its enzymes is necessary to transfer them to a heterologous host for synthesis of various value-added products.

scholarly journals Conversion of 4-Hydroxybutyrate to Acetyl Coenzyme A and Its Anapleurosis in the Metallosphaera sedula 3-Hydroxypropionate/4-Hydroxybutyrate Carbon Fixation Pathway

2014 ◽  
Vol 80 (8) ◽  
pp. 2536-2545 ◽  
Author(s):  
Aaron B. Hawkins ◽  
Michael W. W. Adams ◽  
Robert M. Kelly
Keyword(s):  
Carbon Fixation ◽  
Coenzyme A ◽  
Flux Analysis ◽  
Central Metabolism ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Content Type ◽  
Metallosphaera Sedula ◽  
Acetyl Coenzyme ◽  
Coa Ligase

ABSTRACTThe extremely thermoacidophilic archaeonMetallosphaera sedula(optimum growth temperature, 73°C, pH 2.0) grows chemolithoautotrophically on metal sulfides or molecular hydrogen by employing the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) carbon fixation cycle. This cycle adds two CO2molecules to acetyl coenzyme A (acetyl-CoA) to generate 4HB, which is then rearranged and cleaved to form two acetyl-CoA molecules. Previous metabolic flux analysis showed that two-thirds of central carbon precursor molecules are derived from succinyl-CoA, which is oxidized to malate and oxaloacetate. The remaining one-third is apparently derived from acetyl-CoA. As such, the steps beyond succinyl-CoA are essential for completing the carbon fixation cycle and for anapleurosis of acetyl-CoA. Here, the final four enzymes of the 3HP/4HB cycle, 4-hydroxybutyrate-CoA ligase (AMP forming) (Msed_0406), 4-hydroxybutyryl-CoA dehydratase (Msed_1321), crotonyl-CoA hydratase/(S)-3-hydroxybutyryl-CoA dehydrogenase (Msed_0399), and acetoacetyl-CoA β-ketothiolase (Msed_0656), were produced recombinantly inEscherichia coli, combinedin vitro, and shown to convert 4HB to acetyl-CoA. Metabolic pathways connecting CO2fixation and central metabolism were examined using a gas-intensive bioreactor system in whichM. sedulawas grown under autotrophic (CO2-limited) and heterotrophic conditions. Transcriptomic analysis revealed the importance of the 3HP/4HB pathway in supplying acetyl-CoA to anabolic pathways generating intermediates inM. sedulametabolism. The results indicated that flux between the succinate and acetyl-CoA branches in the 3HP/4HB pathway is governed by 4-hydroxybutyrate-CoA ligase, possibly regulated posttranslationally by the protein acetyltransferase (Pat)/Sir2-dependent system. Taken together, this work confirms the final four steps of the 3HP/4HB pathway, thereby providing the framework for examining connections between CO2fixation and central metabolism inM. sedula.

scholarly journals Simultaneous Fermentation of Glucose and Xylose to Butanol by Clostridium sp. Strain BOH3

2014 ◽  
Vol 80 (15) ◽  
pp. 4771-4778 ◽  
Author(s):  
Fengxue Xin ◽  
Yi-Rui Wu ◽  
Jianzhong He
Keyword(s):  
Transcriptional Repression ◽  
Fermentation Process ◽  
Value Added ◽  
Xylose Isomerase ◽  
Xylose Utilization ◽  
Lignocellulosic Hydrolysates ◽  
Content Type ◽  
Hemicellulosic Hydrolysate ◽  
Attractive Candidate ◽  
Value Added Products

ABSTRACTCellulose and hemicellulose constitute the major components in sustainable feedstocks which could be used as substrates for biofuel generation. However, following hydrolysis to monomer sugars, the solventogenicClostridiumwill preferentially consume glucose due to transcriptional repression of xylose utilization genes. This is one of the major barriers in optimizing lignocellulosic hydrolysates that produce butanol. Unlike studies on existing bacteria, this study demonstrates that newly reportedClostridiumsp. strain BOH3 is capable of fermenting 60 g/liter of xylose to 14.9 g/liter butanol, which is similar to the 14.5 g/liter butanol produced from 60 g/liter of glucose. More importantly, strain BOH3 consumes glucose and xylose simultaneously, which is shown by its capability for generating 11.7 g/liter butanol from a horticultural waste cellulosic hydrolysate containing 39.8 g/liter glucose and 20.5 g/liter xylose, as well as producing 11.9 g/liter butanol from another horticultural waste hemicellulosic hydrolysate containing 58.3 g/liter xylose and 5.9 g/liter glucose. The high-xylose-utilization capability of strain BOH3 is attributed to its high xylose-isomerase (0.97 U/mg protein) and xylulokinase (1.16 U/mg protein) activities compared to the low-xylose-utilizing solventogenic strains, such asClostridiumsp. strain G117. Interestingly, strain BOH3 was also found to produce riboflavin at 110.5 mg/liter from xylose and 76.8 mg/liter from glucose during the fermentation process. In summary,Clostridiumsp. strain BOH3 is an attractive candidate for application in efficiently converting lignocellulosic hydrolysates to biofuels and other value-added products, such as riboflavin.

The impacts of Chinese direct investment in Thailand on the Sino-Thai bilateral trade

2016 ◽  
Vol 9 (1) ◽  
pp. 24-39 ◽  
Author(s):  
Mathavee Keorite ◽  
Huang Pan
Keyword(s):  
Direct Investment ◽  
Design Methodology ◽  
Bilateral Trade ◽  
Raw Materials ◽  
Value Added ◽  
Trade Surplus ◽  
Content Type ◽  
Practical Implications ◽  
Determinant Factor ◽  
Value Added Products

Purpose – The purpose of this paper is to investigate the impacts of Chinese direct investment in Thailand on the Sino-Thai bilateral trade. The economic relationship between Thailand and China has been strengthened through both trade and Chinese direct investment in Thailand for past decades. Design/methodology/approach – AR(p) model was used to examine the effects of Chinese direct investment on both Thailand exports and Thailand imports. Findings – This paper shows that Chinese direct investment in Thailand has contributed to the decrease of intermediate goods of Thailand exports to China. On the other hand, Chinese direct investment has contributed to the increase of finished products of Thailand exports to China. In addition, Chinese direct investment in Thailand has contributed to increase of Thailand imports from China. This suggests that strengthening cooperation for economic growth in either of the two countries can generate mutual benefits through trade. Research limitations/implications – The studies focus only on the effects of foreign direct investment (FDI) on trade, while the effects of trade on FDI are neglected. Practical implications – Policies should be devised to reduce reliance on exports of raw and semi-raw materials by turning on to final products with more value-added products and should improve the equality of infrastructure in the country to attract more FDI into the economy. Originality/value – This paper provides evidence that Chinese direct investment in Thailand is an important determinant factor of the rapid growth of the bilateral trade. It also shows that the appreciation of Thai Baht against Chinese RMB is associated with a decrease in Thailand trade surplus in the bilateral trade.

Mahua (Madhuca longifolia) flowers: review on processing and biological properties

2019 ◽  
Vol 49 (6) ◽  
pp. 1153-1163 ◽  
Author(s):  
Alok Mishra ◽  
Amrita Poonia
Keyword(s):  
Skin Diseases ◽  
Value Added ◽  
Food Products ◽  
Storage Conditions ◽  
Biological Properties ◽  
Content Type ◽  
Post Harvest ◽  
Madhuca Longifolia ◽  
Handling Practices ◽  
Value Added Products

Purpose This paper aims to review the recent advances in processing and utilization of Madhuca longifolia flowers to address its potential as an industrial ingredient. Design/methodology/approach The paper analyzes the harvesting practices of flowers and recent works on the value addition. Findings Mahua flowers are rich source of natural sugars (glucose, fructose, sucrose, etc.) and hence are deliberately used for liquor production by tribal besides various food products, namely, Mahua ladoo, barfi, kheer, sweet puri and as grain staple. Mahuain medicine has been curing people since ages such as in rakhtpitta, diarrhoea and skin diseases and as aphrodisiac, galactagogue, carminative, antihelmenthic, antibacterial and antioxidant. Mahua candy, cake, ready to serve beverages, toffee, squash, ladoo, bars, etc. have been developed as value-added products. However, such a wonderful nature’s gift remains underused due to post harvest spoilage. Practical implications Improvement in storage facilities and processing of flowers after harvesting and drying will lead to enhanced availability of flowers for industrial purposes for food, feed and fodder. More value-added products can be prepared by the preparation of flower-juice concentrate, as well as efforts are made to produce powder from the flowers. Originality/value Post-harvest spoilage of Mahua flowers due to improper collection and handling practices, and filthy storage conditions is the major limitation of Mahua flowers to be used as a potential industrial ingredient. An improvement in collection, handling and pre-processing practices can diversify its use from liquor production to various value-added and functional food products at an industrial scale.

European consumer preference for African dried fruits

2015 ◽  
Vol 117 (7) ◽  
pp. 1886-1902 ◽  
Author(s):  
Roselyne Alphonce ◽  
Anna Temu ◽  
Valerie Lengard Almli
Keyword(s):  
Fair Trade ◽  
Consumer Preferences ◽  
Descriptive Analysis ◽  
Value Added ◽  
Consumer Preference ◽  
Content Type ◽  
Dried Fruits ◽  
European Consumer ◽  
Dried Fruit ◽  
Value Added Products

Purpose – The purpose of this paper is to assess European consumer preference and willingness to pay (WTP) for tropical dried fruits from Africa. The paper specifically investigates sensory and credence characteristics driving consumer preferences. Design/methodology/approach – Data on sensory descriptive analysis and hedonic evaluation for seven samples representing three fruit types: mango, pineapple and banana, were collected together with data on Country of Origin (COO) preferences and WTP for conventional, organic and fair-trade labelled dried fruits, among Norwegian consumers (n=96). Findings – The results show that consumer preferences for a dried fruit are affected significantly by its typical aroma intensity and consumers are willing to pay a premium for both organic and fair-trade products. Two consumer groups expressing distinct COO preferences for tropical dried fruits and a third group with no country preferences are revealed. Originality/value – This study provides useful insights for dried fruit producers and market strategists in tropical countries attempting to position value-added products for maximum revenue.

Development of value added products from the leaf powders of dehydrated less utilized green leafy vegetables

2015 ◽  
Vol 45 (2) ◽  
pp. 302-309
Author(s):  
Pallavi Joshi ◽  
Beena Mathur
Keyword(s):  
Nutritive Value ◽  
Value Added ◽  
Nutritional Composition ◽  
Leafy Vegetables ◽  
Appreciable Amount ◽  
Micronutrient Deficiencies ◽  
Limited Information ◽  
Content Type ◽  
Green Leafy Vegetables ◽  
Value Added Products

Purpose – The purpose of this paper is to analyze the nutritional composition and the acceptability of value-added products prepared from the dehydrated leaf mixture of underutilized green leafy vegetables (GLVs). GLVs are dense in micronutrients and are of great importance to the nutrition of population in developing countries. Nutritive value of commonly consumed GLVs has been studied extensively, but there is limited information available on nutritive value and acceptability of unconventional leafy vegetables. Design/methodology/approach – The nutritional potential and acceptability of leaf mixtures (LMs) prepared from the less-utilized leaves of beet root (Beta vulgaris), carrot (Daucus carota), cauliflower (Brassica oleracea) and turnip (Brassica rapa) which are usually discarded or are used as animal fodder were analyzed in the present study. The LM was prepared by mixing the powders of above-mentioned greens in a definite ratio (1:2:1:1). The LM was analyzed for the proximate, mineral composition (Ca, P, Fe, Cu, Zn, Mn and Mg) and antinutritional factors (oxalate and phenols). In total, 20 different recipes with different levels (0, 5, 10, 15 and 20 per cent) of LM incorporation were prepared and were assessed for quality on the basis of sensory attributes. Findings – The LM contains appreciable amount of proteins, fat, fiber, carbohydrate and calorific value, mineral elements and generally low levels of antinutrients. Products were well-accepted to the level of 10 per cent. Protein, iron and calcium content was significantly (p < 0.05) higher in the LM-incorporated recipes, and the increase was directly proportional to the level of LM incorporated. Originality/value – Dehydrated GLVs are concentrate source of micronutrients and can be used in product formulation. Value addition of traditional products with dehydrated GLVs can be advocated as a feasible food-based approach to combat micronutrient deficiencies.

Is social upgrading occurring in South Asia’s apparel industry?

2017 ◽  
Vol 13 (3) ◽  
pp. 226-243 ◽  
Author(s):  
Amira Khattak ◽  
Nigel Haworth ◽  
Christina Stringer ◽  
Maureen Benson-Rea
Keyword(s):  
International Business ◽  
Multinational Enterprises ◽  
Social Impact ◽  
Value Added ◽  
Content Type ◽  
Theoretical Approaches ◽  
Economic Upgrading ◽  
The Relationship ◽  
Value Added Products ◽  
Social Upgrading

Purpose This paper aims to examine the relationship between economic upgrading (implementing higher value-added activities) and social upgrading (improvements in workers’ rights and employment) of supplier firms in global value chains (GVCs) governed by multinational enterprises (MNEs). This paper answers Buckley and Ghauri’s (2004) and Buckley and Strange (2015) calls to incorporate other theoretical approaches within the international business (IB) literature. Furthermore, the paper also responds to Lee and Gereffi (2015) argument, published in Critical perspectives on international business, of the need to incorporate the social impact of upgrading in the IB literature. Design/methodology/approach Semi-structured interviews were undertaken with representatives from five supplier firms each in Bangladesh and Sri Lanka, as well as with industry representatives. Findings Governance patterns within GVCs can create the conditions for economic upgrading leading to social upgrading achievements. Institutional factors also affect the conditions for social upgrading. Although moving to higher value-added activities is critical for supplier firms, this does not necessarily lead to social upgrading. This paper’s research findings suggest that the combination of economic and social upgrading is positively associated with suppliers manufacturing high value-added products and operating in relational networks. In contrast, economic upgrading, by itself, was limited to those firms manufacturing low value-added products, typically those in captive networks. Originality value This research is among an emerging body of literature seeking to integrate the GVC literature with the IB field. Importantly, it also contributes to the GVC literature by providing insight into an under-theorized aspect – the relationship between social and economic upgrading.

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

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.

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

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.

Socioeconomic effects of pension spending: evidence from Spain

2020 ◽  
Vol 47 (5) ◽  
pp. 599-617
Author(s):  
Fernando Bermejo ◽  
Eladio Febrero ◽  
Andre Fernandes Tomon Avelino
Keyword(s):  
Peer Review ◽  
Social Protection ◽  
Pension System ◽  
Decomposition Analysis ◽  
Value Added ◽  
Total Output ◽  
Alternative View ◽  
Input Output ◽  
Structural Decomposition Analysis ◽  
Content Type

PurposeThe purpose of this study is to provide broader understanding of the significant role that the pension system has in the Spanish economy by estimating the sectoral production, employment and income sustained by pensioners' consumption.Design/methodology/approachBased on input–output tables by the World Input–Output Database and consumption data from the Household Budget Survey by the Spanish Statistical Office, a demoeconomic model is applied to quantify the direct impacts, indirect impacts from interindustry links and induced impacts from income–consumption connections over a nine-year period (2006–2014). Then, the factors driving the evolution of total output, employment and value added during such period have been examined by using structural decomposition analysis.FindingsThe growing participation of consumption by pensioner households in final demand had proven crucial during the 2008 crisis to alleviate the negative trend in production and employment derived from the collapse in consumption suffered by the rest of households.Practical implicationsDetermining the underlying factors driving changes in both employment and income during the 2008 crisis can be of interest in political decision-making on the sustainability of the Spanish pension system.Social implicationsThe results of estimating both the employment and income supported by pensioners' consumption reveal the significant stabilizing effect of the public spending on pensions, particularly during the 2008 crisis.Originality/valueThe current Spanish approach of attaining the pension system sustainability by merely reducing social protection costs ignores the adverse consequences of a lower pensioners' demand. This paper addresses an alternative view in which pension spending is not considered a burden on economic growth but rather a means of improving the level of production and employment.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-01-2019-0047

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