Biology subjects

Shlosberg, Y.

Publications and source records attributed to Shlosberg, Y..

11 recordsLinked to original sources

bioRxiv2024

Photoelectricity generation from beet juice in a bio-electrochemical cell

The world is striving for the development of novel clean energy technologies that can replace the utilization of fossil fuels, and assist in the struggle against climate change. A unique approach that does not involve any carbon emission is bio-photo electrochemical cells (BPECs). This method integrates live organisms with an electrochemical system, while native redox species that exist in the organisms can generate dark and photo electrical current. Such systems were previously shown using photosynthetic micro and macro organisms in which the photocurrent mostly derives from photosynthesis. Another electron source was reported to originate from cherries which consist of pigments and enhance the production of the strong electron donor ascorbic acid under solar irradiation. In this work, we show the ability to produce electrical and photoelectrical current from beet juice. We apply cyclic voltammetry and fluorescence methods to show that among the major components that play a role in the current and photocurrent generation are NADPH and flavins.

bioengineering↗

bioRxiv2024

Bio-electricity production from Fibroblasts and their cultivation media.

The recent understanding of the critical future damage that might happen on earth by climate change has urged scientists to initiate new creative ideas for clean energy technologies that will reduce carbon emissions. A promising approach is the utilization of living cells as electron donors in bio-electrochemical cells (BECs). This concept has been intensively studied for micro-organisms such as non-photosynthetic bacteria, cyanobacteria, and microalgae, but not for mammalian cells. In this work, we report for the first-time integrating live fibroblast cells in a BEC to produce electrical current that is about 3 times higher than intact micro-organisms. Furthermore, we apply 2D-fluorescence and electrochemical measurements to show that like in micro-organisms based BECs, NADH and flavins play a role in the electron mediation between the cells and the anode. Finally, we show that the cultivation medium of fibroblasts also consists of redox species that may produce dark and photocurrent.

bioengineering↗

bioRxiv2023

Non-photosynthetic bacteria produce photocurrent mediated by NADH.

In recent years, the concern from the global climate change has driven an urgent need to develop clean energy technologies that do not involve combustion process that emit carbon into the atmosphere. A promising concept is microbial fuel cells that utilize bacteria as electron donors in a bio-electrochemical cell performing a direct electron transfer via conductive protein complexes or by secretion of redox active metabolites such as quinone or phenazine derivatives. In the case of photosynthetic bacteria (cyanobacteria) electrons can also be extracted from the photosynthetic pathway mediated mostly by NADH and NADPH. In this work, we show for the first time that the intact non-photosynthetic bacteria Escherichia coli can produce photocurrent that is enhanced upon addition of an exogenous electron mediator. Furthermore, we apply 2D-fluorescence measurement to show that NADH is released from the bacterial cells, which may apply as a native electron mediator in microbial fuel cells.

bioengineering↗

bioRxiv2023

Photocurrent production from cherries in a bio-electrochemical cell.

In recent years, big efforts are done to develop new clean energy technologies that will supply the increasing energy demand without contaminating the environment. One of the approaches is the utilization of live organisms as electron donors in bio-electrochemical cells. Photosynthetic organisms may apply for photocurrent generation, releasing NADPH molecules that are formed in the photosynthetic pathway. In this work, we show for the first time that photocurrent can be harvested directly from a cherry fruit associated with a bio-electrochemical cell. Furthermore, we apply electrochemical and spectroscopic methods to show that NADH in the fruit plays a major role in electric current production.

bioengineering↗

bioRxiv2022

Redox-active molecules in bacterial cultivation media produce photocurrent.

In recent years, global climate change has urged the importance of developing new clean energy technologies that may replace the combustion of fossil fuels and help to reduce carbon emissions. A promising, yet intrinsically complex solution, is the utilization of bacteria as electron donors in microbial fuel cells (MFCs). In this work, we show that just the cultivation media for bacterial growth, which is based on yeast extract, is sufficient for generating electrical current in a bio-electrochemical cell (BEC). We apply cyclic voltammetry and 2-dimensional fluorescence spectroscopy to identify redox active molecules such as NADH, NAD+, and flavines that may play key roles in electron donation. Finally, we show that upon illumination, current production is enhanced 2-fold. This photocurrent is generated by a variety of metabolites capable of photochemical reduction, enabling them to donate electrons at the anode of the BEC. Future investigations into the role of culture media versus that of living cells in MFCs may aid in reducing overall production and maintenance costs, and enhance power output performance.

bioengineering↗

bioRxiv2022

Direct electricity production from green onion's roots

In recent years, extensive scientific efforts have been conducted to develop clean bio-energy technologies. A promising approach that has been under development for more than a hundred years is the microbial fuel cell (MFC) which utilizes exo-electrogenic bacteria as an electron source in a bio-electrochemical cell. The viability of bacteria in soil MFCs can be maintained by integrating plant roots which release organic materials that feed the bacteria. In this work, we show that rather than organic compounds, roots also release redox species that can produce electricity in a bio-fuel cell. We first study the reduction of the electron acceptor Cytochrome C by green onion roots. We integrate green onion roots into a bio-fuel cell to produce a continuous bias-free electric current for more than 24 h in the dark. This current is enhanced upon irradiation of light on the onions leaves. We apply cyclic voltammetry and 2D-fluorescence measurements to show that NADH and NADPH act as major electron mediators between the roots and the anode, while their concentration in the external root matrix is increased upon irradiation of the leaves. Finally, we show that roots can contribute to energy storage by charging a supercapacitor.

bioengineering↗

bioRxiv2022

Trichodesmium Erythraeum produces a higher photocurrent than other cyanobacterial species in bio-photo electrochemical cells.

In recent years, the increase in world energy consumption, and the worries from potential future disasters that may derive from climate change have inspired the motivation to develop renewable energy technologies. One of the promising methods is the utilization of whole bacterial cells to produce photocurrent in a bio-photo electrochemical cell (BPEC). The photocurrent derives from the photosynthesis pathway, while the redox couple NADP+/NADPH perform cyclic electron mediation between photosystem I inside the cells, and the anode. Over the years, various cyanobacterial species were utilized in diverse BPECs setups, while the photocurrent was enhanced by the addition of natural electron mediators such as NAD+, NADP+, Cytochrome C, Vitamin B1, and the artificial mediator potassium ferricyanide. The cyanobacterium Trichodesmium Erythraeum (Te) is a marine species that consist of high content of Phycocyanin and Phycoerythrin pigments that play a major role in photosynthesis enhancement. In this work, we produce for the first-time photocurrent from Te. We apply 2D-fluorescence measurements to detect its NADPH secretion and show that its photocurrent production is enhanced as a function of increasing electrolyte salinity. Finally, we produce photocurrent from additional cyanobacterial species: Synechocystis sp. PCC6803, Synechococcus elongatus PCC 7942, Acaryochloris marina MBIC 11017, and Spirulina, using their cultivation medium as electrolytes in the BPEC. We show that TE produces a photocurrent intensity that is significantly greater than all other species with and without the addition of exogenous electron mediators. The utilization of TE may pave the way toward the establishment of marine clean energy technologies.

microbiology↗

bioRxiv2021

Identification of bacteria by poly-aromatic hydrocarbons biosensors

Human health is consistently threatened by different species of pathogenic bacteria. To fight the spread of diseases, it is important to develop rapid methods for bacterial identification. Over the years, different kinds of biosensors were developed for this cause. Another environmental risk are poly-aromatic hydrocarbons (PAHs) that may be emitted from industrial facilities and pollute environmental water and soil. One of the methods for their purification is conducted by the addition of bacteria that can degrade the PAHs, while the bacteria itself can be filtrated at the end of the process. Although many studies reported monitoring of the PAHs degradation by fluorescence, not much attention was dedicated to studying the influence of the PAHs on the intrinsic fluorescence of the degrading bacteria. In this work, we apply synchronous fluorescence (SF) measurements to study the ability of the 5 PAHs: 9-Antracene carboxylic acid (9ACA), Pyrene, Perylene, Pentacene, and Chrysene to interact with bacteria and change its fluorescence spectra. We show that upon incubation of each PAH with the bacterium E.coli only the 2 PAHs 9ACA and Perylene cause an intensity decrease in the emission at {lambda} = 300 - 375 nm, which derives from the emission of Tyrosine and Tryptophane (TT). Also, we show that upon incubation of 9ACA and Perylene with 5 different pathogenic bacteria, the intensity increase or decrease in the TT emission is unique to each bacterial species. Based on this observation, we suggest that the PAHs 9ACA and Perylene can be utilized as biosensors for bacterial identification.

microbiology↗

bioRxiv2021

A new replication medium enables a rapid identification of {varphi}x-174 virus by synchronous fluorescence of Tryptophan.

Development of rapid methods for detection of virus particles based on their intrinsic fluorescence is challenging. Pure viruses may be detected in filtered solutions, based on the strong fluorescence of the amino acid Tryptophan (Trp) in their proteins. Nevertheless, Trp also exists in high quantities in the hosts and host cultivation media. In this work, we show that a separation of the bacteriophage{varphi} x-174 from its E. coli host (grown on the standard cultivation medium "Nutrient Agar") by simple extraction and filtration is not sufficient for its detection based on the intrinsic fluorescence since ~70 % of the Trp fluorescence is derived from impurities. We formulate a new cultivation medium with very low Trp concentration. We apply synchronous fluorescence measurements to show that no Trp fluorescence is detected in the extract solution upon incubation of this medium substrate with ammonium acetate extraction buffer. Finally, we detect{varphi} x-174 based on the spectral fingerprint of its intrinsic Trp content by synchronous fluorescence measurements. The concept of coupling intrinsic fluorescence-based methods to impurities reduction in the source, may pave the way towards future development of simple, cheap, and rapid methods for detection of viral pathogens.

microbiology↗

bioRxiv2021

Harvesting electrical current from intact plant leaves

Here, we show that it is possible to harvest photocurrent directly from unprocessed plant tissues from terrestrial or aquatic environments in bio-photoelectrochemical cells (BPECs) and use the current to produce molecular H2. The source of electrons is shown to originate from the Photosystem II water-oxidation reaction and utilizes exported mediating molecules, especially NADPH. The photocurrent production is dependent on the concentration of the photosynthetic complexes, as an increase in total chlorophyll and oxygen evolution rates lead to increased photocurrent rates. The permeability of the outer leaf surface is another important factor in photocurrent harvesting. Different tissues produce photocurrent densities in the range of [~] 1 - 10 mA / cm2 which is significantly higher than microorganism-based BPECs. The relatively high photocurrent and the simplicity of the plants BPEC may pave the way toward the development of future applicative photosynthetic based energy technologies.

bioengineering↗

bioRxiv2021

Bioelectricity generation from live marine photosynthetic macroalgae

Conversion of solar energy into electrical current by photosynthetic organisms has the potential to produce clean energy. Previously reported bio-photoelectrochemical cells (BPECs) have utilized unicellular photosynthetic microorganisms. In this study, we describe for the first time BPECs that utilize intact live marine macroalgae (seaweeds) in natural seawater or saline buffer or natural seawater. The BPECs produce electrical currents from of >50mA/cm2, from both light-dependent (photosynthesis) and light independent processes. These values are significantly greater than the current densities that have been reported for single-cell microorganisms. The photocurrent is inhibited by the Photosystem II inhibitor DCMU, indicating that the source of light-driven electrons is from water oxidation via NADPH and other reduced molecules. We show here that intact seaweed cultures can be used in a large-scale BPEC containing seawater that produces bias-free photocurrent. The ability to produce bioelectricity from intact seaweeds may pave the way to future development of a low-cost energy technology using BPECs.

bioengineering↗