Engineering All-Round Cellulase for Bioethanol Production.

One strategy to decrease both the consumption of crude oil and environmental damage is through the production of bioethanol from biomass. Cellulolytic enzyme stability and enzymatic hydrolysis play important roles in the bioethanol process. However, the gradually increased ethanol concentration often reduces enzyme activity and leads to inactivation, thereby limiting the final ethanol yield. Herein, we employed an optimized Two-Gene Recombination Process (2GenReP) approach to evolve the exemplary cellulase CBHI for practical bioethanol fermentation. Two all-round CBHI variants (named as R2 and R4) were obtained with simultaneously improved ethanol resistance, organic solvent inhibitor tolerance, and enzymolysis stability in simultaneous saccharification and fermentation (SSF). Notably, CBHI R4 had a 7.0- to 34.5-fold enhanced catalytic efficiency (kcat/KM) in the presence/absence of ethanol. Employing the evolved CBHI R2 and R4 in the 1G bioethanol process resulted in up to 10.27% (6.7 g/L) improved ethanol yield (ethanol concentration) than non-cellulase, which was far more beyond than other optimization strategies. Besides bioenergy fields, this transferable protein engineering routine holds the potential to generate all-round enzymes that meet the requirement in biotransformation and bioenergy fields.

Bioconversion of corn fiber to bioethanol: Status and perspectives.

Due to the rising demand for green energy, bioethanol has attracted increasing attention from academia and industry. Limited by the bottleneck of bioethanol yield in traditional corn starch dry milling processes, an increasing number of studies focus on fully utilizing all corn ingredients, especially kernel fiber, to further improve the bioethanol yield. This mini-review addresses the technological challenges and opportunities on the way to achieving the efficient conversion of corn fiber. Significant advances during the review period include the detailed characterization of different forms of corn kernel fiber and the development of off-line and in-situ conversion strategies. Lessons from cellulosic ethanol technologies offer new ways to utilize corn fiber in traditional processes. However, the commercialization of corn kernel fiber conversion may be hampered by enzyme cost, conversion efficiency, and overall process economics. Thus, future studies should address these technical limitations.

Solvent-Free Hydrogenation of 5-Hydroxymethylfurfural and Furfural to Furanyl Alcohols and their Self-Condensation Polymers.

2,5-Bis(hydroxymethyl)furan (BHMF) as well as furfuryl alcohol (FFA) are considered as highly valuable biomass-derived alcohols resembling aromatic monomers in polymer synthesis. Herein, a series of cobaltic nitrogen-doped carbon (Co-NC) catalysts calcinated at different temperatures were synthesized and tested for the solvent-free hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare BHMF. It was found that the Co-NC catalyst calcinated at 600 °C (Co-NC-600) exhibited a superior catalytic activity in the hydrogenation reaction mainly due to the doping of graphitic N, which probably facilitated the polarization of H2 to afford H+ and H- . Consequently, Co-NC-600 offered a high BHMF/FFA yield greater than 90 % with a nearly complete conversion of HMF/furfural (FF) at the optimal conditions (80 °C, 4 h, and 5 MPa H2 ). After the hydrogenation reaction, Co-NC catalyst was facilely recycled by magnetic separation, and the obtained BHMF/FFA was then successfully transformed into hypercrosslinked polymers with an excellent CO2 /H2 storage capacity comparable to aromatic hydroxymethyl polymers. Therefore, this is a novel and facile two-step pathway for the conversion of biomass-derived HMF/FF towards functional polymers from both industrial and environmental perspectives.

Oxidative Esterification of 5-Hydroxymethylfurfural with an N-doped Carbon-supported CoCu Bimetallic Catalyst.

The direct fabrication of furan-2,5-dimethylcarboxylate (FDMC), a promising renewable monomer, from biomass-derived 5-hydroxymethylfurfural (HMF) is a cutting-edge process. In this contribution, an elaborately designed N-doped carbon-supported CoCu bimetallic catalyst (Cox Cuy -NC; x/y=9:1, 7:3, 4:6, which represents the designed molar ratio of Co and Cu in the catalyst), which could offer a desirable FDMC yield of 95 % under mild and base-free conditions (Co7 Cu3 -NC, 2 bar O2 , 80 °C, 4 h) is described for the oxidative esterification of HMF. Notably, an FDMC formation rate of 6.1 molFDMC molCo -1 h-1 was achieved over Co7 Cu3 -NC, which represents the highest catalytic efficiency so far among Co-based catalytic systems. It has been demonstrated that Cu-doping in Co7 Cu3 -NC catalyst brings about more active sites (Co-Nx species) with stronger molecular oxygen activation ability. The increase of surface N content of Co7 Cu3 -NC also improves basicity of the catalyst, which favors the hydrogen abstraction process during the HMF oxidative esterification reaction. These findings may pave an efficient and green way for the synthesis of sustainable bio-based polymer monomers.

Mussel-inspired degradable antibacterial polydopamine/silica nanoparticle for rapid hemostasis.

High-performance hemostasis becomes increasingly essential in civilian and military trauma. However, available topical hemostats still exist various drawbacks and side-effects. Herein, a silica nanoparticle coated with polydopamine (PDA/SiNP) with good degradability, antibacterial performance was developed for hemorrhage control. PDA/SiNP formed a porous network via lyophilization and rendered material with phenol hydroxyls, aminos, proper hydrophobicity, promising for further cells aggregation and inducing clotting. The degradation behaviors in vitro indicated that the weight loss of PDA/SiNP could attain approximately 40% just after 24 h. All results demonstrated that clotting time of blood was shortened by nearly 150 s for PDA/SiNP compared with that of commercial Celox in vitro hemostasis. PDA/SiNP could significantly accelerate coagulation by activating the extrinsic pathway of the coagulation cascade, adhering platelets and aggregating erythrocytes. Therefore, not only the PDA/SiNP achieved adequate hemostasis with low exothermic effects, but also blood loss was remarkably reduced in the femoral artery and vein injury, liver injury models. Importantly, PDA/SiNP exhibited long-lasting inhibition of Escherichia coli even after 208 h. Also, the hemolysis of PDA/SiNP with low cytotoxicity was much lower, while erythrocytes maintained regular morphology. Thus, amorphous nanoscale PDA/SiNP provided a new avenue for design of silica hemostats and nonmetallic ion antimicrobial.

A novel rhodamine B-based "off-on'' fluorescent sensor for selective recognition of copper (II) ions.

A novel rhodamine based sensor RBH was developed and synthesized by rhodamine B with 3-methyl-2-benzothiazolinone hydrazone, which exhibited high selectivity and sensitivity for sensing Cu2+ ions in the presence of other important relevant metal ions in aqueous acetonitrile. As an "off-on" fluorescent sensor, RBH exhibited a UV-vis absorption increase at 570 nm and a 132-fold significant fluorescence enhancement at 580 nm with a distinct color change from colorless to purple upon the addition of Cu2+ ions. The fluorescence intensity of RBH is linear with the Cu2+ ions concentration with low limit of detection. Furthermore, the sensor RBH has been successfully utilized for fluorescence imaging of Cu2+ ions in living cells. The sensor could potentially recognize Cu2+ ions in biological system.

Genetic Variations in the Kir6.2 Subunit (KCNJ11) of Pancreatic ATP-Sensitive Potassium Channel Gene Are Associated with Insulin Response to Glucose Loading and Early Onset of Type 2 Diabetes in Childhood and Adolescence in Taiwan.

To investigate the role of E23K polymorphism of the KCNJ11 gene on early onset of type 2 diabetes in school-aged children/adolescents in Taiwan, we recruited 38 subjects with type 2 diabetes (ages 18.6 ± 6.6 years; body mass index percentiles 83.3 ± 15.4) and 69 normal controls (ages 17.3 ± 3.8 years; body mass index percentiles 56.7 ± 29.0) from a national surveillance for childhood/adolescent diabetes in Taiwan. We searched for the E23K polymorphism of the KCNJ11 gene. We found that type 2 diabetic subjects had higher carrier rate of E23K polymorphism of KCNJ11 gene than control subjects (P = 0.044). After adjusting for age, gender, body mass index percentiles, and fasting plasma insulin, the E23K polymorphism contributed to an increased risk for type 2 diabetes (P = 0.047). K23-allele-containing genotypes conferring increased plasma insulin level during OGTT in normal subjects. However, the diabetic subjects with the K23-allele-containing genotypes had lower fasting plasma insulin levels after adjustment of age and BMI percentiles. In conclusion, the E23K variant of the KCNJ11 gene conferred higher susceptibility to type 2 diabetes in children/adolescents. Furthermore, in normal glucose-tolerant children/adolescents, K23 allele carriers had a higher insulin response to oral glucose loading.