Background

One of the most important challenges facing society is the development of clean and sustainable processes for production of fuels and chemicals. Semiartificial photosynthesis is an exciting area of research targeting the production of fuels from light, where biocatalysts (enzymes or microorganisms) can be coupled with synthetic light harvesting materials originating so-called biohybrid systems. Most biohybrids were developed using chemically produced semiconductors, which require environmentally unfriendly and expensive synthesis and in most of the systems an electron mediator was required for production of the fuels. One promising alternative is the use of biohybrids constructed using semiconductor nanoparticles that are biologically produced by the involved microorganisms (called biogenic semiconductor). The synthesis of biogenic semiconductor nanoparticles is an eco-friendly and costeffective process to obtain functional nanomaterials with unique features.

Biohybrids have been constructed based on biogenic nanoparticles of CdS and AgInS₂ /In₂S₃ as semiconductors.

Technology Overview

Microbial-based biohybrid systems comprise microorganisms coupled with biogenic CdSMoS₂ nanoparticles doped with biogenic nanoparticles of metals selected from the platinum group metals. The microorganisms of the biohybrid system are selected from anaerobic bacteria capable of generating hydrogen sulphide (H₂S). The biogenic CdSMoS₂ nanoparticles of the present invention have a much-improved H₂ production performance with light as energy source, from 3 to 17-fold more than previously described biohybrids constructed with only CdS. This is a green technology since the metal nanoparticles are produced using microorganisms under mild operation conditions relative to chemically synthesized metal nanoparticles that require high temperatures and pressure for the synthesis. This technology can use light as the only energy source for H₂ production.

No electron mediator is needed during production of H₂ or other compounds, as opposite to the biohybrid systems using chemically synthesized semiconductor nanoparticles. The microbial-based biohybrid system is obtained by using microorganisms such as anaerobic bacteria grown in media with a sulphur source and incubated with cadmium and molybdenum. These two metals react with the H₂S while this is produced by the bacteria originating CdSMoS₂ nanoparticles that are biogenically synthesized. After that, the microbial CdSMoS₂ are dopped with nanoparticles of platinum group metals, also produced biogenically by the anaerobic bacteria. In the end, microbial-metal dopped CdSMoS₂ biohybrids are obtained, composed by anaerobic bacteria coupled to the two types of biogenic nanoparticles.

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Stage of Development

Technology Readiness Level (TRL): 3

Benefits

These characteristics make the present technology a green and low-cost process for H₂ production from light, for example from solar energy.

Furthermore, the presently disclosed microbial-based biohybrid system can also be used to produce other value compounds such as acetate, ethanol, formate, methane, or lactate from light.

Microbial-based Biohybrid System Comprising Biogenic Semiconductor Nanoparticles

Patents

IP Status