Zhen-Peng Zhang

Stereological assessment of extracellular polymeric substances, exo-enzymes, and specific bacterial strains in bioaggregates using fluorescence experiments.

This review addresses the introduction of fluorescent molecular tags into exo-enzymes and extra polymeric substances of bioaggregates and the use of confocal laser scanning microscopy (CLSM) to map their role, purpose and quantitative description of the biological processes they undertake. Multiple color staining coupled with CLSM and fluorescent in situ hybridisation (FISH) and flow cytometry have identified the individual polymeric substances, whether they are proteins, lipids, polysaccharides, nucleic acids or antibodies, as well as the microorganisms in the bioaggregate. Procedures are presented for simultaneous multicolor staining with seven different fluorochromes - SYTOX Blue for nucleic acids; Nile red for lipids; Calcofluor white [CW] for beta-polysaccharides; concanavalin A [Con A] for alpha-poly-saccharides; fluorescein-isothiocyanate [FITC] for proteins; SYTO 63 for live microbial cells and Calcium Green for monitoring calcium levels in the microbial cells. For the distribution of certain microbial strains, metabolic enzymes and extrapolymeric substances to be quantitatively described the generated colored images are converted into digital forms under specific predefined criteria. Procedures and computer software programs (Amira; MATLAB) are presented in order to quantitatively establish grid patterns from the CLSM images. The image is digitized using a threshholding algorithm followed by a reconstruction of the image as a volumetric grid for finite element simulation. The original color image is first converted to a grey followed by resizing, detection and modification of bilevel images and finally a total reversal of the image colors. The grid file is then used by specific computer software (Gambit, Fluent) for further numerical studies incorporating chemical reactions, transport processes and computational fluid dynamics including intra-bioaggregate fluid flow, and heat and mass transfer within the bioaggregate matrix.

Characteristics of rapidly formed hydrogen‐producing granules and biofilms

The physicochemical and microbiological characteristics of rapidly formed hydrogen‐producing granules and biofilms were evaluated in the present study. Microbial species composition was examined using the 16S rDNA‐based separation and sequencing techniques, and spatial distribution and internal structure of microbial components were evaluated by examining the confocal laser scanning microscope (CLSM) images. Phylogenetic analysis indicated that a pure culture of Clostridium pasteurianum‐like bacterium (98% similarity) was found in microbial community of granules and biofilms. It is postulated that containing such a species favored the rapid immobilization of hydrogen‐producing culture. Manure granules and biofilms secreted 24–35 mg extracellulous proteins and 142–175 mg extracellulous polysaccharides in each gram of culture (in VSS). Such a high productivity of extracellulous polymers (ECP), a bio‐glue to facilitate cell‐to‐cell and/or cell‐to‐substratum interaction, may work as the driving forces for the immobilization of C. pasteurianum. As abundant proteins were noted in the granule cores, it can be derived that rapid formation of the hydrogen‐producing granules could be due to the establishment of precursor protein‐rich microbial nuclei. Biotechnol. Bioeng.

Production of Biohydrogen: Current Perspectives and Future Prospects

Publisher Summary Biohydrogen production is considered a development vital to a sustainable global clean energy supply and a promising alternative to conventional fossil fuels, as it has the potential to eliminate most of the problems that fossil fuels create, if not all. The major advantage of energy from biohydrogen is the avoidance of greenhouse gas emissions as the conversion of hydrogen to energy, either via combustion or via fuel cells, results only in pure water. With the use of appropriate technologies, biohydrogen would be the desired clean product of the microbial process. Its production has attracted worldwide attention because of its potential to become an inexhaustible, low-cost, and renewable source of clean energy. Thus biohydrogen is believed to be one of the biofuels of the future. Expert groups of various disciplines throughout the world are focusing on the production and application of biohydrogen, as well as the societal impacts of implementation.Increasing global effort is taking place to develop hydrogen production from biological processes (biohydrogen) as an energy carrier to reduce carbon dioxide emissions and as an alternative for nonrenewable fossil fuels. Biohydrogen, as a renewable biofuel, has the potential to replace current unsustainable hydrogen production technologies, which rely heavily on fossil fuels through electricity generation. Biohydrogen, a high-energy, clean fuel, is regarded as an attractive future energy carrier as its conversion to energy yields only pure water. Unlike bioethanol and biodiesel, biohydrogen production is still in the early stage of development. There are a variety of technologies developed for biohydrogen production, and some laboratory- and pilot-scale fermentation systems have demonstrated a good potential for full-scale implementation. This work presents a review of advances in biohydrogen production focusing on feedstock. Economics, perspectives, and prospects of biohydrogen production are also outlined.

Production of Biohydrogen

Publisher Summary Biohydrogen production is considered a development vital to a sustainable global clean energy supply and a promising alternative to conventional fossil fuels, as it has the potential to eliminate most of the problems that fossil fuels create, if not all. The major advantage of energy from biohydrogen is the avoidance of greenhouse gas emissions as the conversion of hydrogen to energy, either via combustion or via fuel cells, results only in pure water. With the use of appropriate technologies, biohydrogen would be the desired clean product of the microbial process. Its production has attracted worldwide attention because of its potential to become an inexhaustible, low-cost, and renewable source of clean energy. Thus biohydrogen is believed to be one of the biofuels of the future. Expert groups of various disciplines throughout the world are focusing on the production and application of biohydrogen, as well as the societal impacts of implementation.Increasing global effort is taking place to develop hydrogen production from biological processes (biohydrogen) as an energy carrier to reduce carbon dioxide emissions and as an alternative for nonrenewable fossil fuels. Biohydrogen, as a renewable biofuel, has the potential to replace current unsustainable hydrogen production technologies, which rely heavily on fossil fuels through electricity generation. Biohydrogen, a high-energy, clean fuel, is regarded as an attractive future energy carrier as its conversion to energy yields only pure water. Unlike bioethanol and biodiesel, biohydrogen production is still in the early stage of development. There are a variety of technologies developed for biohydrogen production, and some laboratory- and pilot-scale fermentation systems have demonstrated a good potential for full-scale implementation. This work presents a review of advances in biohydrogen production focusing on feedstock. Economics, perspectives, and prospects of biohydrogen production are also outlined.

Chapter 20 – Production of Biohydrogen: Current Perspectives and Future Prospects

Publisher Summary Biohydrogen production is considered a development vital to a sustainable global clean energy supply and a promising alternative to conventional fossil fuels, as it has the potential to eliminate most of the problems that fossil fuels create, if not all. The major advantage of energy from biohydrogen is the avoidance of greenhouse gas emissions as the conversion of hydrogen to energy, either via combustion or via fuel cells, results only in pure water. With the use of appropriate technologies, biohydrogen would be the desired clean product of the microbial process. Its production has attracted worldwide attention because of its potential to become an inexhaustible, low-cost, and renewable source of clean energy. Thus biohydrogen is believed to be one of the biofuels of the future. Expert groups of various disciplines throughout the world are focusing on the production and application of biohydrogen, as well as the societal impacts of implementation.Increasing global effort is taking place to develop hydrogen production from biological processes (biohydrogen) as an energy carrier to reduce carbon dioxide emissions and as an alternative for nonrenewable fossil fuels. Biohydrogen, as a renewable biofuel, has the potential to replace current unsustainable hydrogen production technologies, which rely heavily on fossil fuels through electricity generation. Biohydrogen, a high-energy, clean fuel, is regarded as an attractive future energy carrier as its conversion to energy yields only pure water. Unlike bioethanol and biodiesel, biohydrogen production is still in the early stage of development. There are a variety of technologies developed for biohydrogen production, and some laboratory- and pilot-scale fermentation systems have demonstrated a good potential for full-scale implementation. This work presents a review of advances in biohydrogen production focusing on feedstock. Economics, perspectives, and prospects of biohydrogen production are also outlined.