scholarly journals Glucosamine-6P and glucosamine-1P, respectively an activator and a substrate of rhodococcal ADP-glucose pyrophosphorylases, show a hint to ascertain (actino)bacterial glucosamine metabolism

2020 ◽  
Author(s):  
AE Cereijo ◽  
HM Alvarez ◽  
AA Iglesias ◽  
MD Asencion Diez
Keyword(s):  
Carbon Storage ◽  
Nitrogen Availability ◽  
Carbon Sources ◽  
Catalytic Performance ◽  
Biofuel Production ◽  
Enzyme Promiscuity ◽  
Evolutionary Mechanisms ◽  
Intermediary Metabolite ◽  
Main Regulator ◽  
Temporary Carbon Storage

AbstractRhodococcus spp. are important microorganisms for biotechnological purposes, such as bioremediation and biofuel production. The latter, founded on the oleaginous characteristic (high lipid accumulation) exhibited by many Rhodococcus species when grown in certain carbon sources under low nitrogen availability. These bacteria accumulate glycogen during exponential growth, and the glucan plays a role as an intermediary metabolite for temporary carbon storage related to lipid metabolism. The kinetic and regulatory properties of the ADP-glucose pyrophosphorylase (ADP-GlcPPase) from Rhodococcus jostii supports this hypothesis. The enzyme was found able to use glucosamine-1P as an alternative substrate. Curiously, the activity with glucosamine-1P was sensitive to glucose-6P, the main activator of actinobacterial ADP-GlcPPases. Herein, we report the study of glucosamine-1P related to the activity and regulation of ADP-GlcPPases from R. jostii and R. fascians, with the finding that glucosamine-6P is also a significant activator. Glucosamine-6P, belonging to a node between carbon and nitrogen metabolism, was identified as a main regulator in Actinobacteria. Thus, its effect on rhodococcal ADP-GlcPPases reinforces the function proposed for glycogen as temporary carbon storage. Results indicate that the activity of the studied enzymes using glucosamine-1P as a substrate responds to the activation by several metabolites that improve their catalytic performance, which strongly suggest metabolic feasibility. Then, studying the allosteric regulation exerted on an alternative activity would open two scenarios for consideration: (i) the existence of new molecules/metabolites yet undescribed, and (ii) evolutionary mechanisms underlying enzyme promiscuity that give rise new metabolic features in bacteria.

scholarly journals Conserved Metabolic and Evolutionary Themes in Microbial Degradation of Carbamate Pesticides

2021 ◽  
Vol 12 ◽  
Author(s):  
Harshit Malhotra ◽  
Sukhjeet Kaur ◽  
Prashant S. Phale
Keyword(s):  
Environmental Fate ◽  
Health Sector ◽  
Enzyme Promiscuity ◽  
Adaptive Laboratory Evolution ◽  
Evolutionary Mechanisms ◽  
Ecological Disturbance ◽  
C1 Metabolism ◽  
Carbamate Pesticides ◽  
The Past ◽  
Biochemical Analyses

Carbamate pesticides are widely used as insecticides, nematicides, acaricides, herbicides and fungicides in the agriculture, food and public health sector. However, only a minor fraction of the applied quantity reaches the target organisms. The majority of it persists in the environment, impacting the non-target biota, leading to ecological disturbance. The toxicity of these compounds to biota is mediated through cholinergic and non-cholinergic routes, thereby making their clean-up cardinal. Microbes, specifically bacteria, have adapted to the presence of these compounds by evolving degradation pathways and thus play a major role in their removal from the biosphere. Over the past few decades, various genetic, metabolic and biochemical analyses exploring carbamate degradation in bacteria have revealed certain conserved themes in metabolic pathways like the enzymatic hydrolysis of the carbamate ester or amide linkage, funnelling of aryl carbamates into respective dihydroxy aromatic intermediates, C1 metabolism and nitrogen assimilation. Further, genomic and functional analyses have provided insights on mechanisms like horizontal gene transfer and enzyme promiscuity, which drive the evolution of degradation phenotype. Compartmentalisation of metabolic pathway enzymes serves as an additional strategy that further aids in optimising the degradation efficiency. This review highlights and discusses the conclusions drawn from various analyses over the past few decades; and provides a comprehensive view of the environmental fate, toxicity, metabolic routes, related genes and enzymes as well as evolutionary mechanisms associated with the degradation of widely employed carbamate pesticides. Additionally, various strategies like application of consortia for efficient degradation, metabolic engineering and adaptive laboratory evolution, which aid in improvising remediation efficiency and overcoming the challenges associated with in situ bioremediation are discussed.

scholarly journals Synthesis and characterization of rice husk biochar via hydrothermal carbonization for wastewater treatment and biofuel production

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nazia Hossain ◽  
Sabzoi Nizamuddin ◽  
Gregory Griffin ◽  
Periasamy Selvakannan ◽  
Nabisab Mujawar Mubarak ◽  
...  
Keyword(s):  
Rice Husk ◽  
Agricultural Waste ◽  
Value Added ◽  
Hydrothermal Carbonization ◽  
Catalytic Performance ◽  
Biofuel Production ◽  
Suspension Stability ◽  
Waste Biomass ◽  
Suitable Material ◽  
Rice Husk Biochar

Abstract The recent implication of circular economy in Australia spurred the demand for waste material utilization for value-added product generations on a commercial scale. Therefore, this experimental study emphasized on agricultural waste biomass, rice husk (RH) as potential feedstock to produce valuable products. Rice husk biochar (RB) was obtained at temperature: 180 °C, pressure: 70 bar, reaction time: 20 min with water via hydrothermal carbonization (HTC), and the obtained biochar yield was 57.9%. Enhancement of zeta potential value from − 30.1 to − 10.6 mV in RB presented the higher suspension stability, and improvement of surface area and porosity in RB demonstrated the wastewater adsorption capacity. Along with that, an increase of crystallinity in RB, 60.5%, also indicates the enhancement of the catalytic performance of the material significantly more favorable to improve the adsorption efficiency of transitional compounds. In contrast, an increase of the atomic O/C ratio in RB, 0.51 delineated high breakdown of the cellulosic component, which is favorable for biofuel purpose. 13.98% SiO2 reduction in RB confirmed ash content minimization and better quality of fuel properties. Therefore, the rice husk biochar through HTC can be considered a suitable material for further application to treat wastewater and generate bioenergy.

scholarly journals Hierarchical management of carbon sources is regulated similarly by the CbrA/B systems in Pseudomonas aeruginosa and Pseudomonas putida

Microbiology ◽  
2014 ◽  
Vol 160 (10) ◽  
pp. 2243-2252 ◽  
Author(s):  
Martina Valentini ◽  
Sofía M. García-Mauriño ◽  
Isabel Pérez-Martínez ◽  
Eduardo Santero ◽  
Inés Canosa ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Putida ◽  
Nitrogen Availability ◽  
Carbon Sources ◽  
Signal Transduction Pathway ◽  
Exact Nature ◽  
Energy Status ◽  
Regulatory Systems ◽  
Close Relationship ◽  
Carbon Nitrogen Ratio

The CbrA/B system in pseudomonads is involved in the utilization of carbon sources and carbon catabolite repression (CCR) through the activation of the small RNAs crcZ in Pseudomonas aeruginosa, and crcZ and crcY in Pseudomonas putida. Interestingly, previous works reported that the CbrA/B system activity in P. aeruginosa PAO1 and P. putida KT2442 responded differently to the presence of different carbon sources, thus raising the question of the exact nature of the signal(s) detected by CbrA. Here, we demonstrated that the CbrA/B/CrcZ(Y) signal transduction pathway is similarly activated in the two Pseudomonas species. We show that the CbrA sensor kinase is fully interchangeable between the two species and, moreover, responds similarly to the presence of different carbon sources. In addition, a metabolomics analysis supported the hypothesis that CCR responds to the internal energy status of the cell, as the internal carbon/nitrogen ratio seems to determine CCR and non-CCR conditions. The strong difference found in the 2-oxoglutarate/glutamine ratio between CCR and non-CCR conditions points to the close relationship between carbon and nitrogen availability, or the relationship between the CbrA/B and NtrB/C systems, suggesting that both regulatory systems sense the same sort or interrelated signal.

Evolutionary dynamics of natural product biosynthesis in bacteria

2020 ◽  
Vol 37 (4) ◽  
pp. 566-599 ◽  
Author(s):  
Marc G. Chevrette ◽  
Karina Gutiérrez-García ◽  
Nelly Selem-Mojica ◽  
César Aguilar-Martínez ◽  
Alan Yañez-Olvera ◽  
...  
Keyword(s):  
Natural Products ◽  
Natural Product ◽  
Evolutionary Dynamics ◽  
Chemical Diversity ◽  
Enzyme Promiscuity ◽  
Evolutionary Mechanisms ◽  
Natural Product Biosynthesis ◽  
Metabolic Traits

We review known evolutionary mechanisms underlying the overwhelming chemical diversity of bacterial natural products biosynthesis, focusing on enzyme promiscuity and the evolution of enzymatic domains that enable metabolic traits.

scholarly journals Impact of various media and organic carbon sources on biofuel production potential from Chlorella spp.

3 Biotech ◽  
2016 ◽  
Vol 6 (2) ◽  
Author(s):  
Amit Kumar Sharma ◽  
Pradeepta Kumar Sahoo ◽  
Shailey Singhal ◽  
Alok Patel
Keyword(s):  
Organic Carbon ◽  
Carbon Sources ◽  
Biofuel Production ◽  
Production Potential ◽  
Organic Carbon Sources

scholarly journals Hydrocracking of Calophyllum inophyllum Oil Employing Co and/or Mo Supported on γ-Al2O3 for Biofuel Production

2020 ◽  
Vol 15 (3) ◽  
pp. 743-751
Author(s):  
Wega Trisunaryanti ◽  
Triyono Triyono ◽  
Mohammad Ali Ghoni ◽  
Dyah Ayu Fatmawati ◽  
Puspa Nindro Mahayuwati ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Metal Content ◽  
Liquid Fraction ◽  
Catalytic Performance ◽  
Biofuel Production ◽  
Food Crop ◽  
Wet Impregnation ◽  
Calophyllum Inophyllum ◽  
High Metal ◽  
Calophyllum Inophyllum Oil

Cobalt and/or Molybdenum based catalysts were simply dispersed on γ-Al2O3 through wet impregnation. The set of prepared monometallic and bimetallic catalysts of aCoO/γ-Al2O3, aMoO/γ-Al2O3, aCoOaMoO/γ-Al2O3, and bCoObMoO/γ-Al2O3 were investigated and evaluated in the hydrocracking of Calophyllum inophyllum (CIO) which is not a food crop as well as rich in unsaturated fatty acid that potential to be converted into biofuel. Out of the prepared catalysts, aCoOaMoO/γ-Al2O3 with total   metal content, acidity, and specific surface area of 13.62 wt%, 5.01 mmol.g-1, and 107.67 m2.g-1, respectively, showed the best catalytic performance. The high metal loading of aCoOaMoO/γ-Al2O3 is favorable by producing 65.56 wt% liquid fraction through carbocation formation mechanism. It was selective to produce 8.61 wt% gasoline and 5.01 wt% diesel. Copyright © 2020 BCREC Group. All rights reserved 

Soil carbon storage and carbon sources under different Spartina alterniflora invasion periods in a salt marsh ecosystem

CATENA ◽  
2021 ◽  
Vol 196 ◽  
pp. 104831 ◽  
Author(s):  
Guangliang Zhang ◽  
Junhong Bai ◽  
Qingqing Zhao ◽  
Jia Jia ◽  
Xin Wang ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Soil Carbon ◽  
Carbon Storage ◽  
Spartina Alterniflora ◽  
Carbon Sources ◽  
Soil Carbon Storage ◽  
Spartina Alterniflora Invasion

scholarly journals Preparation and Application of Biochar-Based Catalysts for Biofuel Production

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 346 ◽  
Author(s):  
Feng Cheng ◽  
Xiuwei Li
Keyword(s):  
Hydrothermal Carbonization ◽  
Catalytic Performance ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Biomass Hydrolysis ◽  
Heteroatom Doping ◽  
Tar Reduction ◽  
Alkali Catalysts ◽  
Future Work

Firstly, this paper reviews two main methods for biochar synthesis, namely conventional pyrolysis and hydrothermal carbonization (HTC). The related processes are described, and the influences of biomass nature and reaction conditions, especially temperature, are discussed. Compared to pyrolysis, HTC has advantages for processing high-moisture biomass and producing spherical biochar particles. Secondly, typical features of biochar in comparison with other carbonaceous materials are summarized. They refer to the presence of inorganics, surface functional groups, and local crystalline structures made up of highly conjugated aromatic sheets. Thirdly, various strategies for biochar modification are illustrated. They include activation, surface functionalization, in situ heteroatom doping, and the formation of composites with other materials. An appropriate modification is necessary for biochar used as a catalyst. Fourthly, the applications of biochar-based catalysts in three important processes of biofuel production are reviewed. Sulfonated biochar shows good catalytic performance for biomass hydrolysis and biodiesel production. Biodiesel production can also be catalyzed by biochar-derived or -supported solid-alkali catalysts. Biochar alone and biochar-supported metals are potential catalysts for tar reduction during or after biomass gasification. Lastly, the merits of biochar-based catalysts are summarized. Biochar-based catalysts have great developmental prospects. Future work needs to focus on the study of mechanism and process design.

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