Synergetic Fermentation of Glucose and Glycerol for High-Yield N-Acetylglucosamine Production in Escherichia coli

N-acetylglucosamine (GlcNAc) is an amino sugar that has been widely used in the nutraceutical and pharmaceutical industries. Recently, microbial production of GlcNAc has been developed. One major challenge for efficient biosynthesis of GlcNAc is to achieve appropriate carbon flux distribution between growth and production. Here, a synergistic substrate co-utilization strategy was used to address this challenge. Specifically, glycerol was utilized to support cell growth and generate glutamine and acetyl-CoA, which are amino and acetyl donors, respectively, for GlcNAc biosynthesis, while glucose was retained for GlcNAc production. Thanks to deletion of the 6-phosphofructokinase (PfkA and PfkB) and glucose-6-phosphate dehydrogenase (ZWF) genes, the main glucose catabolism pathways of Escherichia coli were blocked. The resultant mutant showed a severe defect in glucose consumption. Then, the GlcNAc production module containing glucosamine-6-phosphate synthase (GlmS*), glucosamine-6-phosphate N-acetyltransferase (GNA1*) and GlcNAc-6-phosphate phosphatase (YqaB) expression cassettes was introduced into the mutant, to drive the carbon flux from glucose to GlcNAc. Furthermore, co-utilization of glucose and glycerol was achieved by overexpression of glycerol kinase (GlpK) gene. Using the optimized fermentation medium, the final strain produced GlcNAc with a high stoichiometric yield of 0.64 mol/mol glucose. This study offers a promising strategy to address the challenge of distributing carbon flux in GlcNAc production.

Adaptations in metabolism and protein translation give rise to the Crabtree effect in yeast

Aerobic fermentation, also referred to as the Crabtree effect in yeast, is a well-studied phenomenon that allows many eukaryal cells to attain higher growth rates at high glucose availability. Not all yeasts exhibit the Crabtree effect, and it is not known why Crabtree-negative yeasts can grow at rates comparable to Crabtree-positive yeasts. Here, we quantitatively compared two Crabtree-positive yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, and two Crabtree-negative yeasts, Kluyveromyces marxianus and Scheffersomyces stipitis, cultivated under glucose excess conditions. Combining physiological and proteome quantification with genome-scale metabolic modeling, we found that the two groups differ in energy metabolism and translation efficiency. In Crabtree-positive yeasts, the central carbon metabolism flux and proteome allocation favor a glucose utilization strategy minimizing proteome cost as proteins translation parameters, including ribosomal content and/or efficiency, are lower. Crabtree-negative yeasts, however, use a strategy of maximizing ATP yield, accompanied by higher protein translation parameters. Our analyses provide insight into the underlying reasons for the Crabtree effect, demonstrating a coupling to adaptations in both metabolism and protein translation.

Research on the Application of Interaction Design in the Functional Design of Intelligent-home Products

The networking operation of intelligent-home products can expand more functions and bring consumers more in-depth interactive experience. The effective integration of interaction design, intelligence and info tech in intelligent-home products can effectively solve the shortcomings and problems of home market products. Based on this, this paper first analyses the concept and value of product functional interaction design, then studies the functional design of intelligent-home products based on interaction design, and finally gives the utilization strategy of interactive design in the functional design of intelligent-home products.

Research on the Application of Computer BIM Technology in Geotechnical Engineering

BIM Tech on account of its three-dimensional, intuitive, visual, reconfigurable and other aspects of the typical characteristics, has gained more and more attention in the field of architecture and civil engineering, and obtained more in-depth research and application. On account of this, this paper first analyses the concept of IM tech and its utilization value, then studies the specific utilization of computer BIM Tech in geotechnical engineering, and finally gives the utilization strategy of computer BIM Tech in geotechnical engineering.

Strategi Penghimpunan Dan Penyaluran Zakat, Infaq, Shadaqah Pada Lembaga Amil Zakat Infaq Shadaqah Muhammadiyah (LAZISMU) Kota Medan

<p>Management of ZIS in the city of Medan has entered a modernization era where zakat management is directed to amil zakat institutions that specifically deal with the ZIS problem. Now there are many LAZ in Medan, including LAZISMU. Both LAZISMU have enormous potential, because they are under the auspices of the largest Islamic organization in Indonesia. However, in the funding and distribution activities of ZIS in LAZISMU, there is still no promising performance. Some notes show that the number of ZIS that have been funded by these two LAZIS is still relatively low. And the distribution of ZIS has not yet shown maximum results. The research is a field research, namely research conducted or conducted in a specific place using descriptive analysis methods. Descriptive analysis is research that describes clearly and in detail the phenomena that are the subject matter without hypothesizing or doing statistical calculations, which in this case describes clearly and in detail about the main problems that occur in the ZIS collection and utilization strategy in LAZISMU City Field. The results of this study can be concluded that LAZISMU uses its strategic position and utilizes technological advancements to improve the performance of ZIS collection and distribution. </p>