Prog. Chem.

Lignocellulose is a key feedstock for production of bioenergy and biobased products. The structure of lignocellulose is highly complicated. The enzymatic efficiency of lignocellulose is influenced by the congregated structure and components of which. The main cell wall proteins of plant and the potential effects on enzymatic hydrolysis of lignocellulose are reviewed. Study of the enzymatic hydrolysis of lignocellulose from the activities of plant cell wall proteins affords new insight to investigate the mechanisms of enzymatic hydrolysis and efficient hydrolysis ways.Lignocellulose is a key feedstock for production of bioenergy and biobased products. The structure of lignocellulose is highly complicated. The enzymatic efficiency of lignocellulose is influenced by the congregated structure and components of which. The main cell wall proteins of plant and the potential effects on enzymatic hydrolysis of lignocellulose are reviewed. Study of the enzymatic hydrolysis of lignocellulose from the activities of plant cell wall proteins affords new insight to investigate the mechanisms of enzymatic hydrolysis and efficient hydrolysis ways

Enzyme Microb. Technol.

A cellulase synergistic protein named Zea h was purified from fresh postharvest corn stover through sequential treatments. The purified Zea h was homogeneous by PAGE and SDS-PAGE examination, indicating its purity and molecular weight (M,,) of approximately 55.78 kDa. Comparing with cellulase (0.042 FPU) was applied alone in hydrolysis of filter paper, when Zea h (6 mu g) and cellulase were applied together, the hydrolysis rate was increased by a factor of 2 within 1 h, and the total cellulose conversion was increased by a factor of 3 during the 24 It's hydrolysis. Thermal stability analysis revealed that 50.2% of the synergetic activity was recovered when Zea h was incubated in water for 30 min at 100 degrees C, yet the protein was deactivated in high pressure steam (160 degrees C) for 5 min. Studies on the mechanisms of the synergism between Zea h and cellulase showed that, Zea h could increase the adsorption of cellulase onto substrate, and decrease the hydrogen-bond intensity and CrI of substrate. Yet Zea It has no cellulase activity, and has little effect on cellulase stability under the conditions of hydrolysis. It could be concluded that Zea It may modify the structure of filter paper through weakening or rupturing hydrogen bonds, and more it more accessible to cellulase. The unique property of Zea It provides an opportunity for decreasing enzyme loading while retaining the same degree of hydrolysis. (C) 2007 Elsevier Inc. All rights reserved.A cellulase synergistic protein named Zea h was purified from fresh postharvest corn stover through sequential treatments. The purified Zea h was homogeneous by PAGE and SDS-PAGE examination, indicating its purity and molecular weight (M,,) of approximately 55.78 kDa. Comparing with cellulase (0.042 FPU) was applied alone in hydrolysis of filter paper, when Zea h (6 mu g) and cellulase were applied together, the hydrolysis rate was increased by a factor of 2 within 1 h, and the total cellulose conversion was increased by a factor of 3 during the 24 It's hydrolysis. Thermal stability analysis revealed that 50.2% of the synergetic activity was recovered when Zea h was incubated in water for 30 min at 100 degrees C, yet the protein was deactivated in high pressure steam (160 degrees C) for 5 min

Promotion of Carbon Dioxide Biofixation through Metabolic and Enzyme Engineering

Carbon dioxide is a major greenhouse gas, and its fixation and transformation are receiving increasing attention. Biofixation of CO2 is an eco–friendly and efficient way to reduce CO2, and six natural CO2 fixation pathways have been identified in microorganisms and plants. In this review, the six pathways along with the most recent identified variant pathway were firstly comparatively characterized. The key metabolic process and enzymes of the CO2 fixation pathways were also summarized. Next, the enzymes of Rubiscos, biotin-dependent carboxylases, CO dehydrogenase/acetyl-CoA synthase, and 2-oxoacid:ferredoxin oxidoreductases, for transforming inorganic carbon (CO2, CO, and bicarbonate) to organic chemicals, were specially analyzed. Then, the factors including enzyme properties, CO2 concentrating, energy, and reducing power requirements that affect the efficiency of CO2 fixation were discussed. Recent progress in improving CO2 fixation through enzyme and metabolic engineering was then summarized. The artificial CO2 fixation pathways with thermodynamical and/or energetical advantages or benefits and their applications in biosynthesis were included as well. The challenges and prospects of CO2 biofixation and conversion are discussed.</jats:p

Promotion of Carbon Dioxide Biofixation through Metabolic and Enzyme Engineering

Carbon dioxide is a major greenhouse gas, and its fixation and transformation are receiving increasing attention. Biofixation of CO2 is an eco-friendly and efficient way to reduce CO2, and six natural CO2 fixation pathways have been identified in microorganisms and plants. In this review, the six pathways along with the most recent identified variant pathway were firstly comparatively characterized. The key metabolic process and enzymes of the CO2 fixation pathways were also summarized. Next, the enzymes of Rubiscos, biotin-dependent carboxylases, CO dehydrogenase/acetyl-CoA synthase, and 2-oxoacid:ferredoxin oxidoreductases, for transforming inorganic carbon (CO2, CO, and bicarbonate) to organic chemicals, were specially analyzed. Then, the factors including enzyme properties, CO2 concentrating, energy, and reducing power requirements that affect the efficiency of CO2 fixation were discussed. Recent progress in improving CO2 fixation through enzyme and metabolic engineering was then summarized. The artificial CO2 fixation pathways with thermodynamical and/or energetical advantages or benefits and their applications in biosynthesis were included as well. The challenges and prospects of CO2 biofixation and conversion are discussed

Electroautotrophic Microorganisms: Uptaking Extracellular Electron and Catalyzing CO2 Fixation and Synthesis

Electroautotrophic microorganisms can uptake electrons from extracellular solid donors such as metallic iron or steel, electrodes, and symbiotic microbial cells. Fuels and commodity chemicals can be produced from CO2 in a bioelectrochemical system powered by electricity and catalyzed by electroautotrophic microorganisms since they are often able to reduce and fix CO2. Thus, this provides a new and promising strategy to cope with the word energy crisis and greenhouse effect. Metabolic properties and electron uptake abilities of electroautotrophic microorganisms have direct and significant influences on viability and productivity of electrosynthesis processes. In this review, a diversity of microbial physiologies uptaking electrons from iron or steel, electrode and microbial cell, including sulphate reduction, methanogenesis, acetogenesis and nitrate reduction, are respectively summarized in the first place. Then, research progress of electrosynthesis of methane, acetate and other chemicals catalyzed by diverse electroautotrophic microorganisms are reviewed. And strategies for improving CO2 fixation and electrosynthesis efficiency and diversifying the products are emphasized, such as defined co-culture construction, cathode material modification and so on. At last, research efforts in clarifying extracellular electron transfer mechanism, catalyzing microorganisms screening and co-culture construction, and genetic engineering of electroautotrophic microbes are proposed as future directions for researchers

Enhancement of nanofiber elasticity by using wheat glutenin as an addition

The properties of glutenin allow it to be a potential substrate for biomaterial production. In the present study, composite nanofiber was fabricated from polyvinyl alcohol (PVA) and glutenin based on the synergy of them. In the composite nanofiber, glutenin and PVA act as elasticizer and skeleton polymer, respectively. The property of composite nanofiber is markedly superior to that of PVA. For example, the homogeneity and average diameter of nanofiber from PVA/glutenin were increased, while the number and diameter of beads were decreased. Compared to nanofiber from PVA, the elongation and water absorbance of nanofiber from PVA/glutenin were increased by 121 and 150%, respectively. The proposed mechanism of composite nanofiber formation might be non-covalent networks such as hydrogen bond and SS bond that were built up during electrospinning. It is illustrated that the combination of elasticity of glutenin and crosslinking of PVA/glutenin lead to higher water absorbance, looser texture and better mechanical strength