Improving sustainable hydrogen production from green waste: [FeFe]-hydrogenases quantitative gene expression RT-qPCR analysis in presence of autochthonous consortia

Abstract Background Bio-hydrogen production via dark fermentation of low-value waste is a potent and simple mean of recovering energy, maximising the harvesting of reducing equivalents to produce the cleanest fuel amongst renewables. Following several position papers from companies and public bodies, the hydrogen economy is regaining interest, especially in combination with circular economy and the environmental benefits of short local supply chains, aiming at zero net emission of greenhouse gases (GHG). The biomasses attracting the largest interest are agricultural and urban green wastes (pruning of trees, collected leaves, grass clippings from public parks and boulevards), which are usually employed in compost production, with some concerns over the GHG emission during the process. Here, an alternative application of green wastes, low-value compost and intermediate products (partially composted but unsuitable for completing the process) is studied, pointing at the autochthonous microbial consortium as an already selected source of implementation for biomass degradation and hydrogen production. The biocatalysts investigated as mainly relevant for hydrogen production were the [FeFe]-hydrogenases expressed in Clostridia, given their very high turnover rates. Results Bio-hydrogen accumulation was related to the modulation of gene expression of multiple [FeFe]-hydrogenases from two strains (Clostridium beijerinckii AM2 and Clostridium tyrobutyricum AM6) isolated from the same waste. Reverse Transcriptase quantitative PCR (RT-qPCR) was applied over a period of 288 h and the RT-qPCR results showed that C. beijerinckii AM2 prevailed over C. tyrobutyricum AM6 and a high expression modulation of the 6 different [FeFe]-hydrogenase genes of C. beijerinckii in the first 23 h was observed, sustaining cumulative hydrogen production of 0.6 to 1.2 ml H2/g VS (volatile solids). These results are promising in terms of hydrogen yields, given that no pre-treatment was applied, and suggested a complex cellular regulation, linking the performance of dark fermentation with key functional genes involved in bio-H2 production in presence of the autochthonous consortium, with different roles, time, and mode of expression of the involved hydrogenases. Conclusions An applicative outcome of the hydrogenases genes quantitative expression analysis can be foreseen in optimising (on the basis of the acquired functional data) hydrogen production from a nutrient-poor green waste and/or low added value compost, in a perspective of circular bioeconomy.

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Hydrogen production conditions from food waste by dark fermentation with Clostridium beijerinckii KCTC 1785

Biotechnology and Bioprocess Engineering ◽

10.1007/s12257-008-0142-0 ◽

2008 ◽

Vol 13 (4) ◽

pp. 499-504 ◽

Cited By ~ 49

Author(s):

Jung Kon Kim ◽

Le Nhat ◽

Young Nam Chun ◽

Si Wouk Kim

Keyword(s):

Hydrogen Production ◽

Food Waste ◽

Dark Fermentation ◽

Clostridium Beijerinckii ◽

Production Conditions

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Optimization of Hydrogen Production by Co-Culture of Clostridium beijerinckii and Rhodobacter sphaeroides Bacteria

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.93.90 ◽

2014 ◽

Vol 93 ◽

pp. 90-95 ◽

Cited By ~ 4

Author(s):

Roman Zagrodnik

Keyword(s):

Hydrogen Production ◽

Rhodobacter Sphaeroides ◽

Hydrogen Generation ◽

Nitrogen Sources ◽

Dark Fermentation ◽

Single Step ◽

Clostridium Beijerinckii ◽

Hydrogen Yield ◽

Batch Tests ◽

Pure Cultures

The biological methods of hydrogen generation have attracted a significant interest recently. In this work the hybrid system applying both dark fermentation bacteria in co-culture was tested. Objective of this work was to investigate the optimization of different parameters on co-culture of Clostridium beijerinckii DSM-791 and Rhodobacter sphaeroides O.U.001. The effect of glucose concentration (1–5 g/L), temperature and initial pH (6,5–7,5) was analyzed. Moreover the influence of organic nitrogen sources were tested for their capacity to support hydrogen production (yeast extract, peptone, glutamic acid). Fermentations were conducted in batch tests with glucose as sole substrate. Hydrogen production in mixed culture was compared with pure cultures. The process was greatly affected by pH and light/dark bacteria ratio. Liquid metabolites, namely acetic and butyric acids, from the dark fermentation step were the source of organic carbon for photosynthetic bacteria. This increased the hydrogen yield in comparison to single-step dark fermentation to over 4 mol H2/mol glucose. Obtained results showed that combination of photo and dark fermentation may increase hydrogen production and conversion efficiency of complex substrates or wastewaters.

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Evolutionary dynamics of sex-biased gene expression in a young XY system: Insights from the brown algae

10.1101/2021.08.12.455804 ◽

2021 ◽

Author(s):

William J Hatchett ◽

Alexander O Jueterbock ◽

Martina Kopp ◽

James A Coyer ◽

Susana M Coelho ◽

...

Keyword(s):

Gene Expression ◽

Brown Algae ◽

Evolutionary Dynamics ◽

Regulation Of Gene Expression ◽

Sequence Evolution ◽

Turnover Rates ◽

Evolution Of Sex ◽

High Turnover ◽

Evolutionary Forces ◽

Flagellar Proteins

The sex-dependent regulation of gene expression is considered to be the underlying cause of often extensive, sexually dimorphic traits between males and females. Although the nature and degree of sex-biased gene expression has been well-documented in several animal and plant systems, far less is known about the commonality, conservation, recruitment mechanisms and evolution of sex-biased genes in more distant eukaryotic groups. Brown algae are of particular interest for empirical studies on the evolution of sex-biased gene expression, as they have been evolving independently from animals and plants for over one billion years. Here we focus on two brown algal dioecious species, Fucus serratus and Fucus vesiculosus, where male heterogamety (XX/XY) has recently emerged. Using RNA-seq, we study sex-biased gene expression and discuss different evolutionary forces responsible for the evolution of sex-biased genes. We find that both species evolved masculinized transcriptomes, with sex-biased genes allocated mainly to male reproductive tissue, but virtually absent in vegetative tissues. Conserved male-biased genes were enriched in functions related to gamete production, along with sperm competition and include two flagellar proteins under positive selection. In contrast to female-biased genes, which show high turnover rates, male-biased genes reveal remarkable conservation of bias and expression levels between the two species. As observed in other XY systems, male-biased genes also display accelerated rates of coding sequence evolution compared to female-biased or unbiased genes. Our results imply that evolutionary forces affect male and female sex-biased genes differently on structural and regulatory levels. Similarly to evolutionary distant plant and animal lineages, sex-biased gene expression in Fucus evolved during the transition to dioecy to resolve intra-locus sexual conflict arising from anisogamy.

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The effects of metal ions and l-cysteine on hydA gene expression and hydrogen production by Clostridium beijerinckii RZF-1108

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2012.02.144 ◽

2012 ◽

Vol 37 (18) ◽

pp. 13711-13717 ◽

Cited By ~ 33

Author(s):

Xin Zhao ◽

Defeng Xing ◽

Bingfeng Liu ◽

Lu Lu ◽

Jun Zhao ◽

...

Keyword(s):

Gene Expression ◽

Hydrogen Production ◽

Metal Ions ◽

Clostridium Beijerinckii

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Detection of Metal Toxicity Using Natural Phytoplankton as Test Organisms in the Great Lakes

Water Quality Research Journal ◽

10.2166/wqrj.1993.008 ◽

1993 ◽

Vol 28 (1) ◽

pp. 155-176

Author(s):

Mohiddin Munawari ◽

Milos Legner

Keyword(s):

Great Lakes ◽

Metal Toxicity ◽

Structural Changes ◽

System Response ◽

Turnover Rates ◽

High Turnover ◽

Spectra Analysis ◽

Test Organisms ◽

Future Potential ◽

Natural Phytoplankton

Abstract This paper presents an overview of techniques utilizing natural phytoplankton for the detection of metal-Induced stress in the Great Lakes. Both field and laboratory procedures are designed to evaluate either structural changes or functional response of test organisms. This up-to-date compendium provides a choice of techniques, which permits a holistic assessment of the stress caused by toxic metals. Recently introduced techniques, such as normalized size spectra analysis, flow cytometry, and the evaluation of a continuous-flow system response to metal toxicity, are discussed in more detail to explore their future potential. Owing to their key position in the food web, high turnover rates, abundance, and sensitivity to environmental perturbation, phytoplankton serve as reliable early warning indicators of ecosystem deterioration and its restoration.

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Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

Scientific Reports ◽

10.1038/s41598-021-95615-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

R. M. Silva ◽

A. A. Abreu ◽

A. F. Salvador ◽

M. M. Alves ◽

I. C. Neves ◽

...

Keyword(s):

Hydrogen Production ◽

Anaerobic Bacteria ◽

Dark Fermentation ◽

Inorganic Materials ◽

Biohydrogen Production ◽

High Rate ◽

Continuous Reactor ◽

Organic Loading Rate ◽

Fermentation Products ◽

Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

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