Polyhydroxyalkanoates (PHAs) are a diverse family of sustainable bioplastics synthesized by various bacteria, but their high production cost and unstable material properties make them challenging to ...use in commercial applications. Current industrial biotechnology (CIB) employs conventional microbial chassis, leading to high production costs. However, next-generation industrial biotechnology (NGIB) approaches, based on fast-growing and contamination-resistant extremophilic Halomonas spp., allow stable continuous processing and thus economical production of PHAs with stable properties. Halomonas spp. designed and constructed using synthetic biology not only produce low-cost intracellular PHAs but also secrete extracellular soluble products for improved process economics. Next-generation industrial biotechnology is expected to reduce the bioproduction cost and process complexity, leading to successful commercial production of PHAs.
The high production cost, poor thermal and mechanical properties, and unstable quality of polyhydroxyalkanoates (PHAs) are the grand challenges to be addressed before industrialization.Next-generation industrial biotechnology (NGIB) based on extremophiles is emerging to meet most of these challenges.Fast-growing and contamination-resistant Halomonas spp. allow open, unsterile, and continuous fermentations to produce PHAs with low-cost and stable properties.Halomonas spp. constructed by synthetic biology generate large sizes for PHA accumulation and gravity separation or coproduction of extracellular soluble products.
The structure of the Nafion ionomer used in proton-exchange membranes of H(2)/O(2) fuel cells has long been contentious. Using a recently introduced algorithm, we have quantitatively simulated ...previously published small-angle scattering data of hydrated Nafion. The characteristic 'ionomer peak' arises from long parallel but otherwise randomly packed water channels surrounded by partially hydrophilic side branches, forming inverted-micelle cylinders. At 20 vol% water, the water channels have diameters of between 1.8 and 3.5 nm, with an average of 2.4 nm. Nafion crystallites (approximately 10 vol%), which form physical crosslinks that are crucial for the mechanical properties of Nafion films, are elongated and parallel to the water channels, with cross-sections of approximately (5 nm)(2). Simulations for various other models of Nafion, including Gierke's cluster and the polymer-bundle model, do not match the scattering data. The new model can explain important features of Nafion, including fast diffusion of water and protons through Nafion and its persistence at low temperatures.
The scope of the Special Issue entitled "Investigation of High-Performance Electrode Materials: Processing and Storage Mechanism" includes the research on electrodes of high-performance ...electrochemical energy storage and conversion devices (metal ion batteries, non-metallic ion batteries, metal-air batteries, supercapacitors, photocatalysis, electrocatalysis, etc ....
Steel production is a difficult-to-mitigate sector that challenges climate mitigation commitments. Efforts for future decarbonization can benefit from understanding its progress to date. Here we ...report on greenhouse gas emissions from global steel production over the past century (1900-2015) by combining material flow analysis and life cycle assessment. We find that ~45 Gt steel was produced in this period leading to emissions of ~147 Gt CO
-eq. Significant improvement in process efficiency (~67%) was achieved, but was offset by a 44-fold increase in annual steel production, resulting in a 17-fold net increase in annual emissions. Despite some regional technical improvements, the industry's decarbonization progress at the global scale has largely stagnated since 1995 mainly due to expanded production in emerging countries with high carbon intensity. Our analysis of future scenarios indicates that the expected demand expansion in these countries may jeopardize steel industry's prospects for following 1.5 °C emission reduction pathways. To achieve the Paris climate goals, there is an urgent need for rapid implementation of joint supply- and demand-side mitigation measures around the world in consideration of regional conditions.
Next generation industrial biotechnology (NGIB) based on extremophilic bacteria grown under unsterile and continuous way in plastic transparent bioreactors.▪
•Low petroleum prices require innovations ...to make bio-production competitive.•Contamination resistant extremophilic microorganisms can simplify bioprocessing.•Next generation industrial biotechnology (NGIB) is energy and fresh water saving.•NGIB should be operated under open and continuous conditions and easily automated.•NGIB should make bulk chemical production as competitive as chemical processes.
Industrial biotechnology aims to produce bulk chemicals including polymeric materials and biofuels based on bioprocessing sustainable agriculture products such as starch, fatty acids and/or cellulose. However, traditional bioprocesses require bioreactors made of stainless steel, complicated sterilization, difficult and expensive separation procedures as well as well-trained engineers that are able to conduct bioprocessing under sterile conditions, reducing the competitiveness of the bio-products. Amid the continuous low petroleum price, next generation industrial biotechnology (NGIB) allows bioprocessing to be conducted under unsterile (open) conditions using ceramic, cement or plastic bioreactors in a continuous way, it should be an energy, water and substrate saving technology with convenient operation procedure. NGIB also requires less capital investment and reduces demand on highly trained engineers. The foundation for the simplified NGIB is microorganisms that resist contaminations by other microbes, one of the examples is rapid growing halophilic bacteria inoculated under high salt concentration and alkali pH. They have been engineered to produce multiple products in various scales.
Polyhydroxyalkanoates (PHAs) are a diverse family of biopolyesters synthesized by many natural or engineered bacteria. Synthetic biology and DNA-editing approaches have been adopted to engineer cells ...for more efficient PHA production. Recent advances in synthetic biology applied to improve PHA biosynthesis include ribosome-binding site (RBS) optimization, promoter engineering, chromosomal integration, cell morphology engineering, cell growth behavior reprograming, and downstream processing. More importantly, the genome-editing tool clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) has been applied to optimize the PHA synthetic pathway, regulate PHA synthesis-related metabolic flux, and control cell shapes in model organisms, such as Escherichia coli, and non-model organisms, such as Halomonas. These synthetic biology methods and genome-editing tools contribute to controllable PHA molecular weights and compositions, enhanced PHA accumulation, and easy downstream processing.
The bioplastic PHA, which features biodegradability, biocompatibility, and thermoprocessibility, is moving toward low-cost microbial production to replace nondegradable petrochemical plastics.Wild-type or weakly engineered bacteria are insufficient to meet demands for improved PHA structures and low production cost.Synthetic biology and genome-editing approaches can promote PHA synthesis, enlarge cells for more PHA storage, control shape changes, accelerate growth, aid the co-production of multiple products, direct flux toward final products, and make product recovery more convenient.Optimized promoters and RBSs increase the expression of PHA synthesis genes.CRISPR interference and CRISPR/Cas9 are useful for downregulating the expression of multiple genes simultaneously, allowing more flux to be directed to PHA synthesis in an optimized strain.
A newly developed polyacrylamide‐co‐methyl acrylate/spiropyran (SP) hydrogel crosslinked by SP mechanophore demonstrates multi‐stimuli‐responsive and mechanically strong properties. The hydrogels not ...only exhibit thermo‐, photo‐, and mechano‐induced color changes, but also achieve super‐strong mechanical properties (tensile stress of 1.45 MPa, tensile strain of ≈600%, and fracture energy of 7300 J m−2). Due to a reversible structural transformation between spiropyran (a ring‐close) and merocyanine (a ring‐open) states, simple exposure of the hydrogels to white light can reverse color changes and restore mechanical properties. The new design approach for a new mechanoresponsive hydrogel is easily transformative to the development of other mechanophore‐based hydrogels for sensing, imaging, and display applications.
A newly developed poly(acrylamide‐co‐methyl acrylate)/spiropyran hydrogel with multi‐stimuli‐responsive and mechanically strong properties is presented. The resulting hydrogel exhibits reversible changes in color response and mechanical properties, making it promising for sensing, imaging, and display applications.
Emerging studies have shown that circular RNAs could be ideal biomarkers and even potential therapeutic targets for some tumors, including bladder cancer. However, only a few studies have ...investigated the circular RNAs in human bladder cancer. The key circular RNA molecules are closely related to bladder cancer and their roles remain largely unknown. Here, we investigated a novel circular RNA molecule, hsa‐circ‐0003221(circPTK2), which is differentially expressed in bladder carcinoma. Significant differential expression levels of circPTK2 were confirmed with quantitative PCR in 40 pairs of tissue and blood samples from patients with bladder carcinoma. Moreover, circPTK2 levels both in tissue and blood were significantly correlated with several clinicopathologic characteristics, including poor differentiation (P = 0.0103 in tissue, P = 0.024 in blood), N2‐N3 lymph node metastasis (P = 0.0065 in tissue, P = 0.016 in blood), and T(II–III–IV) stage (P = 0.008 in tissue, P = 0.0003 in blood). Quantitative PCR results confirmed that circPTK2 is highly expressed in migrated cells separated by Transwell assay and in metastatic lymph nodes of tumors transplanted in nude mice. In vitro silence of circPTK2 by small interfering RNA inhibited the proliferation and migration of bladder cancer cells. On the contrary, circPTK2 overexpression promoted proliferation and migration. This study showed that circPTK2 promotes proliferation and migration of cells and may be a novel potential biomarker and therapeutic target for bladder cancer diagnosis and therapy.
Hsa_circ_0003221 (circPTK2), a circular RNA molecule closely related to bladder cancer, showed significant differences in the clinical tissue and blood samples of patients with bladder cancer. Further experiments showed that this circular RNA molecule promotes proliferation and cell migration in bladder cancer cells. Our results indicated that circPTK2 may be a new potential biomarker or a target for bladder cancer diagnosis and therapy.
To avoid large open surgery using scaffold transplants, small‐sized cell carriers are employed to repair complexly shaped tissue defects. However, most cell carriers show poor cell adherences and ...viability. Therefore, polyhydroxyalkanoate (PHA), a natural biopolymer, is used to prepare highly open porous microspheres (OPMs) of 300–360 µm in diameter, combining the advantages of microspheres and scaffolds to serve as injectable carriers harboring proliferating stem cells. In addition to the convenient injection to a defected tissue, and in contrast to poor performances of OPMs made of polylactides (PLA OPMs) and traditional less porous hollow microspheres (PHA HMs), PHA OPMs present suitable surface pores of 10–60 µm and interconnected passages with an average size of 8.8 µm, leading to a high in vitro cell adhesion of 93.4%, continuous proliferation for 10 d and improved differentiation of human bone marrow mesenchymal stem cells (hMSCs). PHA OPMs also support stronger osteoblast‐regeneration compared with traditional PHA HMs, PLA OPMs, commercial hyaluronic acid hydrogels, and carrier‐free hMSCs in an ectopic bone‐formation mouse model. PHA OPMs protect cells against stresses during injection, allowing more living cells to proliferate and migrate to damaged tissues. They function like a micro‐Noah's Ark to safely transport cells to a defect tissue.
Combining the advantages of microspheres and scaffolds, highly open porous microspheres (OPMs) made of polyhydroxyalkanoate (PHA) are developed as injectable carriers harboring growing stem cells. The PHA OPMs protect the stem cells from stresses during injection, allowing more living cells to proliferate and migrate to damaged tissues, functioning like a micro‐Noah's Ark to safely transport cells to a designated tissue location for regeneration.
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