ABSTRACT
Space-based biomanufacturing has the potential to improve the sustainability of deep space exploration. To advance biomanufacturing, bioprocessing systems need to be developed for space applications. Here, commercial technologies were assessed to design space bioprocessing systems to supply a liquid amine carbon dioxide scrubber with active carbonic anhydrase produced recombinantly. Design workflows encompassed biomass dewatering of 1 L Escherichia coli cultures through to recombinant protein purification. Non-crew time equivalent system mass (ESM) analyses had limited utility for selecting specific technologies. Instead, bioprocessing system designs focused on minimizing complexity and enabling system versatility. Three designs that differed in biomass dewatering and protein purification approaches had nearly equivalent ESM of 357-522 kg eq. Values from the system complexity metric (SCM), technology readiness level (TRL), integration readiness level (IRL), and degree of crew assistance metric identified a simpler, less costly, and easier to operate design for automated biomass dewatering, cell lysis, and protein affinity purification.
ABSTRACT
A promising approach for the synthesis of high value reduced compounds is to couple bacteria to the cathode of an electrochemical cell, with delivery of electrons from the electrode driving reductive biosynthesis in the bacteria. Such systems have been used to reduce CO2 to acetate and other C-based compounds. Here, we report an electrosynthetic system that couples a diazotrophic, photoautotrophic bacterium, Rhodopseudomonas palustris TIE-1, to the cathode of an electrochemical cell through the mediator H2 that allows reductive capture of both CO2 and N2 with all of the energy coming from the electrode and infrared (IR) photons. R. palustris TIE-1 was shown to utilize a narrow band of IR radiation centered around 850 nm to support growth under both photoheterotrophic, non-diazotrophic and photoautotrophic, diazotrophic conditions with growth rates similar to those achieved using broad spectrum incandescent light. The bacteria were also successfully cultured in the cathodic compartment of an electrochemical cell with the sole source of electrons coming from electrochemically generated H2, supporting reduction of both CO2 and N2 using 850 nm photons as an energy source. Growth rates were similar to non-electrochemical conditions, revealing that the electrochemical system can fully support bacterial growth. Faradaic efficiencies for N2 and CO2 reduction were 8.5 and 47%, respectively. These results demonstrate that a microbial-electrode hybrid system can be used to achieve reduction and capture of both CO2 and N2 using low energy IR radiation and electrons provided by an electrode.
ABSTRACT
Mesenchymal stem/stromal cells (MSCs) have gained considerable popularity owing to the vast possibilities and lack of ethical constraints and risks normally associated with other stem cells, such as embryonic stem cells. However, they are morphologically indistinguishable from fibroblasts. This review aims to assess the similarities and differences between the two cell types, and the possible relationship between them. We found that the two cells seem almost identical with respect to their surface immunophenotype, proliferation, and differentiation capacities and even, to an extent, their gene expression profiles and immunomodulatory capacities. There are some differences in capability between the two cells, with MSCs being more efficient than fibroblasts. Even so, the similarities are so striking, that, if we were to follow the current criteria provided by the International Society for Cellular Therapy, fibroblasts ought to be named as MSCs. One promising marker is their DNA methylation profiles. Nonetheless, without any other marker to differentiate between the cells in the first place, it would be difficult to find a definitive marker. Interestingly, the differences observed between the two cells have also been observed between young and old MSCs. This also seems to be true of certain cell surface markers. Therefore, it is possible that fibroblasts are in fact aged MSCs and that the two cells are the same.
