Immobilization techniques for biocatalysts

Over the last decades, the number of bioprocesses successfully run at industrial scale has been increasingly growing mainly due to the development of technologies for the immobilization of enzymes and microorganisms. These immobilization techniques allow an easy recovery and reuse of the biocatalysts with the subsequent reduction of materials and down-stream costs . The modern biotechnology makes use yet of immobilization supports to intensify industrial biotransformation reactions based on the use of whole cells of microorganisms and enzymes. Environmental technologies for wastewater and air treatment take advantage of immobilization of microorganisms, e.g. biofilms of rotating discs, percolating filters or cell aggregates in the activated sludge process, where the recycling of microorganisms relies on the capability of microorganisms to flocculate. The immobilization/aggregation or retention (e.g. in MBR) mechanisms can help to operate stable wastewater treatment. In order to take on challenges of stability and efficiency of bioremediation processes related to the introduction of microorganisms and enzymes for the targeted elimination of pollutants, the strategy of MINOTAURUS relied on the immobilization of these biocatalysts. The project applied these approaches on various scales from lab to pilot plants, taking advantage of the natural propensity of microorganisms and enzymes to attach on support material for the development of advanced bioremediation technologies. The technologies initially selected for development within MINOTAURUS were: bioaugmentation of membrane reactors using immobilized cells to degrade EDCs and PPCPS, packed-bed bioreactors bioaugmented with immobilized cells for the remediation of CAH-contaminated groundwater via aerobic cometabolism, bioaugmentation of packed-bed bioreactors for the elimination of MTBE/TBA/BTEX with immobilized cells from groundwater, biofilm at the surface of solid-state electrodes serving as electron donor or acceptor, rhizosphere as natural support material for biodegrading microorganisms, immobilization of enzymes for the elimination of EDCs, MTBE, and PPCPs (immobilization of laccase on fumed-silica and membranes or via cross-linked enzyme aggregates of laccase)

Increased Collagen Turnover Impairs Tendon Microstructure and Stability in Integrin α2β1-Deficient Mice

Integrins are a family of transmembrane proteins, involved in substrate recognition and cell adhesion in cross-talk with the extra cellular matrix. In this study, we investigated the influence of integrin α2β1 on tendons, another collagen type I-rich tissue of the musculoskeletal system. Morphological, as well as functional, parameters were analyzed in vivo and in vitro, comparing wild-type against integrin α2β1 deficiency. Tenocytes lacking integrin α2β1 produced more collagen in vitro, which is similar to the situation in osseous tissue. Fibril morphology and biomechanical strength proved to be altered, as integrin α2β1 deficiency led to significantly smaller fibrils as well as changes in dynamic E-modulus in vivo. This discrepancy can be explained by a higher collagen turnover: integrin α2β1-deficient cells produced more matrix, and tendons contained more residual C-terminal fragments of type I collagen, as well as an increased matrix metalloproteinase-2 activity. A greatly decreased percentage of non-collagenous proteins may be the cause of changes in fibril diameter regulation and increased the proteolytic degradation of collagen in the integrin-deficient tendons. The results reveal a significant impact of integrin α2β1 on collagen modifications in tendons. Its role in tendon pathologies, like chronic degradation, will be the subject of future investigations