Microbial Paper: Cellulose Fiber-based Photo-Absorber Producing Hydrogen Gas from Acetate using Dry-Stabilized Rhodopseudomonas palustris

Abstract

The microstructure and reactivity of a novel nonwoven cellulose fiber cellular biocomposite (microbial paper) was studied relative to long-term stabilization of potentially any microorganism. Cells were incorporated during the papermaking process as an integral component of a highly porous cellular biocomposite that can be dry stabilized. Hydrogen gas production from acetate via the activity of the nitrogenases in Rhodopseudomonas palustris CGA009, entrapped at a very high concentration, in hand-made microbial paper was sustained for > 1000 h at a rate of 4.0 ± 0.28 mmol H2/m 2 h -1 following rehydration. This rate is 2x and 10x greater than previously reported H2 production rates by Rps. palustris latex coatings that were dried on polyester and non-dried formulations applied to the surface of paper, respectively. By vacuumdewatering and controlled drying steps to the microbial papermaking process and incorporating blends of microfibrillar (MFC), softwood (SW), and hardwood (HW) cellulose fibers, microbial paper films were fabricated that produced H2 gas at 3.94 ± 1.07 mmol H 2 /m 2 h -1 and retain up to 60 mg/m -2 dry cell weight (DCW) of Rps. palustris. The MFC content appears to determine the final cell load and may affect gas/moisture mass transfer properties of the biocomposite.

A Microalgae Biocomposite-Integrated Spinning Disk Bioreactor (SDBR): Toward a Scalable Engineering Approach for Bioprocess Intensification in Light-Driven CO2 Absorption Applications

“…Biocomposite materials that concentrate and deposit thin, adhesive layers of photosynthetic cells in the form of highly structured multilayered composites on flexible surfaces or cells concentrated and embedded in porous papers have been reported. , Planar biocomposites enable uniform solar illumination, and this geometry can be easily compared with the photo efficiency of natural leaves or photovoltaics. Such multilayered biocomposites of highly concentrated cells have the potential to increase the light-harvesting efficiency of nongrowing cyanobacteria or microalgae well beyond that observed in conventional photo bioreactors with the added advantage of substantially reducing water use.…”

“…Biocomposites can be produced by depositing concentrated immobilized micro-organisms on the surface of substrate material, which is a technique referred to as a biocoating. The support material can be flexible, nonporous substrates (polyester, metals) or nonwoven porous substrates (papers), often utilizing an adhesive or a latex binder to stabilize the living cells to create an environmental biocatalyst. − These biocoatings can be formed by drawdown or inkjet deposition, convective sedimentation assembly, dielectrophoresis, or coated onto papers. ,− …”

Immobilising Microalgae and Cyanobacteria as Biocomposites: New Opportunities to Intensify Algae Biotechnology and Bioprocessing

“…Synechococcus PCC6301 immobilised with different latex emulsions on a carbon electrode maintained nearly 100% of its photosynthetic activity upon rehydration [81]. Photosynthetic microorganisms have also been immobilised onto filter paper using acrylate copolymer latex polymers to produce artificial leaf biocomposites for hydrogen production with a service life of over 1000 h. The specific photosynthetic rate was enhanced by up to 10 times compared to the suspension controls [82,83].…”

Process intensification technologies for CO2 capture and conversion – a review

“…The photo-efficiency of these microorganisms is low, thus there is a technology development need in this area to improve their efficiency. Some of the conventional intensification technologies shown in Table 1 can be deployed in conjunction with more novel techniques of cell immobilisation such as in biocomposites where highly concentrated, living but non-growing microorganisms are incorporated within the structure of either nonporous substrates (polyesters, metals) or non-woven porous substrates (papers) [65][66][67].…”