Journal of biotechnology最新文献

Acetaldehyde, a carcinogen widely present in various beverages and the natural environment, necessitates convenient and efficient detection methods. In this work, two different host strains were used to develop a sensitive, convenient, and efficient whole-cell optical biosensor for acetaldehyde detection. Acetaldehyde dehydrogenase (AldH) was displayed on the cell surface of Saccharomyces cerevisiae and E. coli using flocculin protein and the N-terminal ice nucleation protein (INP), respectively. The successful construction of yeast and bacteria surface display platforms was confirmed by laser scanning confocal microscopy. Then, the optimal AldH-display system for yeast and bacteria was confirmed. The optimum reaction conditions were determined by changing testing temperatures and pH values. The differences between the two display systems were compared. The highest whole-cell activities of yeast and bacteria under optimal conditions were 3.68 ± 0.07 U/mL/OD₆₀₀ for BY-S6G and 6.95 ± 0.04 U/mL/OD₆₀₀ for E-32-I_rA. The strains with the best performance were chosen for the detection of acetaldehyde in wine and other beverage samples and showed substrate specificity and accuracy, in which the recovery rate ranged between 94.4 % and 110.1 %. The results demonstrated that the AldH surface display strains could be used as an optical biosensor to detect acetaldehyde in beverages and red wine.

The natural blue colorant C-phycocyanin (C-PC) has many potential applications but its poor heat stability limits its commercial use. This study compares the production and thermal stability of C-PC from two cyanobacteria: the thermophilic Thermosynechococcus sp. TUBT-T01 and the mesophilic Synechococcus cedrorum TISTR8589. Thermosynechococcus sp. produced nearly 1.9-fold more C-PC than S. cedrorum. Batch adsorption using a chromatographic cationic ion exchange resin (Streamline Direct HST1) was used to effectively purify the C-PC. The equilibrium adsorption capacity (Q_eq) of the resin for C-PC was the highest at pH 5. At this pH, the Q_eq for the thermophilic C-PC was 5.5 ± 0.1 mg mL⁻¹ , whereas for the mesophilic C-PC it was 1.5 ± 0.2 mg mL⁻¹ . Purification increased the concentration of the thermophilic C-PC by 5.9-fold, and that of mesophilic C-PC by 4.2-fold. The purity ratios of the final products from the two cyanobacteria were similar at ∼2.2. At 60 °C and pH 7, the C-PC of Thermosynechococcus sp. had ∼12-times longer half-life than the mesophilic C-PC; however, the productivity of the thermophilic C-PC was comparatively low because of a low biomass productivity of Thermosynechococcus sp.

The branch of biomimetics has witnessed a profound impact on the field of biosensor technology, reflected in sustainable analyte detection. A vast array of biosensor platforms with improved/upgraded performance have been developed and reported. No wonder the motivation from the field of biomimetics has a huge impact on generating detection systems with escalated degrees of manipulation and tunability at different levels. More recently, biomimetic biosensor technology has found potential in constructing bio-inspired materials such as aptamers, MIPs, nanozymes, DNAzymes, Synzymes, etc. to be integrated with biosensor fabrication. The establishment of a sensing setup is not limited to the bioreceptor fabrication; the construction of transducing element using biomimetic material have been reported too. Moreover, to serve a biosensing of target analyte from a fatal diseased sample different biomimetic architectures can be designed that mimic in-vivo microenvironmental surroundings to get an exact microenvironment equivalent to natural conditions leading towards designing of a precise treatment strategy. This research area is ever-evolving as there is a scope for upgradation and refinement due to advancing technologies including nanotechnology, biomimetic nanomaterials, microfluidics, optical sensors, etc. This review is an attempt to comprehend and juxtapose the very primary innovations in the field of biomimetic biosensor technology to realize its comprehensive and wide-range scope and possibilities.

The immune system is regulated by dendritic cells (DCs), which are highly specialized cells for presenting antigens. They are thought of as natural sentinels that start the immune response triggered by naive T cells against invasive infections. DCs participate in the initial stage of muscle damage in conjunction with monocytes, macrophages, and myogenic cells. The goal of this study was to determine whether DCs might mitigate tissue damage and aid in the regeneration of the gastrocnemius muscle following envenomation with Bothrops jararacussu venom (BjV). Mature bone marrow dendritic cells (BMDCs) were used to treat mice in an experimental envenomation model with BjV by activation with lipopolysaccharide (LPS). BMDCs were injected into the gastrocnemius muscle at the same site of the BjV injury, in a single dose, 3 h after envenomation, and envenoming effects were observed at different periods for 7 days. In both untreated (NT) and treated (T) groups tissue necrosis, leukocyte influx, and hemorrhage at the injury site were observed. Results showed an increase in serum and tissue CK as well as IL-6, TNF-α, and IL-1β release in the first hours after envenoming. In contrast, after treatment with BMDCs results obtained demonstrated an attenuated local effect with a small leukocyte influx, decreased or non-existent necrosis and hemorrhage, as well as a reduction in both serum and tissue CK levels as well as cytokine release and, consequently, the onset of a moderate regenerative process. The present study's findings concluded that BjV causes a severe inflammatory reaction at the site of injury and that treating envenoming with BMDCs in the muscle was crucial for minimizing damage to the muscle and the inflammatory reaction and promoting the early onset of the tissue repair process.

Efficient regeneration of NAD⁺ remains a significant challenge for oxidative biotransformations. In order to identify enzymes with higher activity and stability, a panel of NADH oxidases (Nox) was investigated in the regeneration of nicotinamide cofactors for the oxidation of hydroxymethyl furfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA). We present novel Nox that exhibit remarkable catalytic activities, elevated thermal and pH stabilities, and higher intrinsic flavin loadings, thus eliminating the need for external flavin addition. The kinetic analysis of the NADH oxidases indicates that AdNox, GdNox, CmNox, and LvNox exhibit V_max values of 86 U/mg, 50 U/mg, 4.3 U/mg, and 23 U/mg, respectively. When these NADH oxidases were applied in a HMF oxidation reaction, LvNox demonstrated the highest HMFCA yield of 97 % in the presence of 0.1 mM NAD and 10 mM HMF. In contrast to previously reported NADH oxidases from the same family, these NADH oxidases naturally accept NADPH as a substrate. Rapid kinetics experiments identified the oxidative reaction as the rate-limiting step of the reaction. NADH oxidases achieved high atom economy, a high reaction mass efficiency and a low process mass intensity. The findings contribute significantly to the field of biocatalysis and offer potential avenues for more environmentally friendly cofactor regeneration in chemical synthesis.