Inhibition Effect of <i>Pseudomonas stutzeri</i> on the Corrosion of X70 Pipeline Steel Caused by Sulfate-Reducing Bacteria

Microbiologically influenced corrosion (MIC) is a common phenomenon in water treatment, shipping, construction, marine and other industries. Sulfate-reducing bacteria (SRB) often lead to MIC. In this paper, a strain of Pseudomonas stutzeri (P. stutzeri) with the ability to inhibit SRB corrosion is isolated from the soil through enrichment culture. P. stutzeri is a short, rod-shaped, white and transparent colony with denitrification ability. Our 16SrDNA sequencing results verify the properties of P. stutzeri strains. The growth conditions of P. stutzeri bacteria and SRB are similar, and the optimal culture conditions are about 30 °C, pH 7, and the stable stage is reached in about seven days. The bacteria can coexist in the same growth environment. Using the weight loss method, electrochemical experiments and composition analysis techniques we found that P. stutzeri can inhibit the corrosion of X70 steel by SRB at 20~40 °C, pH 6~8. Furthermore, long-term tests at 3, 6 and 9 months reveal that P. stutzeri can effectively inhibit the corrosion of X70 steel caused by SRB

Maximizing production of sugar and ultrafine lignin particles from recalcitrant softwood by different acids-assisted organosolvolysis and fast pyrolysis

Lignocellulosic biomass is an abundantly available feedstock for the sustainable production of chemicals and materials. However, total conversion of three major components within biomass (hemicellulose, cellulose and lignin) into chemicals and materials via single hydrolysis or fast pyrolysis remains a challenge because of the heterogeneous structure and recalcitrant nature of biomass, which is especially evident for softwood. In order to address these challenges, with ethylene glycol as solvent and different acids (HCl, HClO4, H2SO4, H3PO4, HCOOH, C3H6O3, or CH3COOH) as catalyst, an integrated process consisting of different acids-assisted organosolvolysis and subsequent fast pyrolysis was proposed for maximizing conversion of softwood into sugars (hemicellulosic and pyrolytic sugars) and ultrafine lignin. Mechanistic insight into acids-assisted organosolvolysis of recalcitrant pine indicated that, acid pKa and H+ concentrations were vital factors influencing the deconstruction of softwood into cellulose-rich fraction, hemicellulosic sugars and high purity ultrafine lignin. This considerably enhanced the heterolytic cleavage of cellulose into levoglucosan (LG) in subsequent fast pyrolysis. The highest LG yield of 44.45 wt% was realized by HCl due to its high pKa value and maximum H+ concentration. Total conversion efficiencies of strong acids-assisted integrated process were superior to those from medium strong and weak acids-assisted process with the highest total conversion efficiency of 61.61 wt% achieved by HClO4 and that of HCl and H2SO4 over 50.00 wt%. Moreover, prewashing feedstocks with HCl solution could effectively improve the total conversion efficiency as well as the purity and uniformity of ultrafine lignin. These findings help to provide an efficient process for maximizing the conversion efficiency of recalcitrant softwood for the production of sugars and ultrafine lignin. (C) 2020 Elsevier Ltd. All rights reserved

Asymmetric Construction of Carbon–Fluorine Quaternary Stereogenic Centers via Synergistic Pd/Cu Catalysis

We developed an asymmetric decarboxylative allylic alkylation of vinylethylene carbonates with α-fluoro pyridinyl acetates through a synergistic palladium/copper catalysis. This protocol provides chiral allylic alcohol with carbon–fluorine quaternary stereogenic centers in good yield with good enantioselectivities and excellent regioselectivities. The utility of this approach was further demonstrated via a gram-scale experiment and derivatizations of the product

De novo assembly of a haplotype-resolved human genome

The human genome is diploid, and knowledge of the variants on each chromosome is important for the interpretation of genomic information. Here we report the assembly of a haplotype-resolved diploid genome without using a reference genome. Our pipeline relies on fosmid pooling together with whole-genome shotgun strategies, based solely on next-generation sequencing and hierarchical assembly methods. We applied our sequencing method to the genome of an Asian individual and generated a 5.15-Gb assembled genome with a haplotype N50 of 484 kb. Our analysis identified previously undetected indels and 7.49 Mb of novel coding sequences that could not be aligned to the human reference genome, which include at least six predicted genes. This haplotype-resolved genome represents the most complete de novo human genome assembly to date. Application of our approach to identify individual haplotype differences should aid in translating genotypes to phenotypes for the development of personalized medicine

De novo assembly of a haplotype-resolved human genome.

The human genome is diploid, and knowledge of the variants on each chromosome is important for the interpretation of genomic information. Here we report the assembly of a haplotype-resolved diploid genome without using a reference genome. Our pipeline relies on fosmid pooling together with whole-genome shotgun strategies, based solely on next-generation sequencing and hierarchical assembly methods. We applied our sequencing method to the genome of an Asian individual and generated a 5.15-Gb assembled genome with a haplotype N50 of 484 kb. Our analysis identified previously undetected indels and 7.49 Mb of novel coding sequences that could not be aligned to the human reference genome, which include at least six predicted genes. This haplotype-resolved genome represents the most complete de novo human genome assembly to date. Application of our approach to identify individual haplotype differences should aid in translating genotypes to phenotypes for the development of personalized medicine