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Covering: up to the end of 2022Natural products (NPs) have found uses in medicine, food, cosmetics, materials science, environmental protection, and other fields related to our life. Their beneficial properties along with potential toxicities make the detection and discrimination of NPs crucial for their applications. Owing to the merits of low cost and simple operation, optical sensor arrays, including colorimetric and fluorometric sensor arrays, have been widely applied in the detection of small molecule NPs and discrimination of structurally similar small molecule NPs or complex mixtures of NPs. This review provides a brief introduction to the optical sensor array and focuses on its progress toward the detection and discrimination of NPs. We summarized the design principle of sensor arrays toward various NPs (

With the rapid development of society, the risk management of personal health and assets has become an important content that cannot be ignored in all walks of life. With the in-depth advancement of risk management, most of the construction risks of prefabricated buildings adopt qualitative research based on experience and intuitive judgment and quantitative research on quantitative mathematical statistics, but there are few models for risk assessment of prefabricated buildings with dynamic characteristics to adapt to the rapid development of prefabricated buildings and the lack of prefabricated construction in various stages and complex environments, with risk prediction and effective response capabilities. Based on this, this paper attempts to propose a fuzzy neural network risk research method for prefabricated building construction, making full use of the fuzzy neural network’s qualitative knowledge expression and quantitative numerical computing advantages, to establish a set of strong fault tolerance and better adaptive ability: fuzzy neural network evaluation model for extensive prefabricated building construction risk. Through the design of the fuzzy network model structure, the membership vector of the qualitative and quantitative indicators of the fuzzy comprehensive evaluation of the risk of prefabricated building construction is used as the input vector of the neural network, and the evaluation result is used as the output of the neural network. The samples were trained, programmed, and debugged, and it was found that the training results of the samples were in good agreement with the expected output results, which further verified the feasibility and applicability of the fuzzy neural network in the risk assessment process of prefabricated buildings. It is of good guiding significance to conduct continuous observation and formulate effective risk aversion and response plans.

Linkage isomers (α-2,3- or α-2,6-linkage) of sialylated N-glycans are involved in the emergence and progression of some diseases, so they are of great significance for diagnosing and monitoring diseases. However, the qualitative and quantitative analysis of sialylated N-glycan linkage isomers remains challenging due to their low abundance and limited isomeric separation techniques. Herein, we developed a novel strategy integrating one-step sialic acid derivatization, positive charge-sensitive separation and highly sensitive detection based on microfluidic capillary electrophoresis-mass spectrometry (MCE-MS) for fast and specific analysis of α-2,3- and α-2,6-linked sialylated N-glycan isomers. A kind of easily charged long-chain amino compound was screened first for one-step sialic acid derivatization so that only α-2,3- and α-2,6-linked isomers can be quickly and efficiently separated within 10 min by MCE due to the difference in structural conformation, whose separation mechanism was further theoretically supported by molecular dynamic simulation. In addition, different sialylated N-glycans were separated in order according to the number of sialic acids, so that a migration time-based prediction of the number of sialic acids was achieved. Finally, the sialylated N-glycome of human serum was profiled within 10 min and 6 of the 52 detected sialylated N-glycans could be potential diagnostic biomarkers of cervical cancer (CC), whose α-2,3- and α-2,6-linked isomers were distinguished by α-2,3Neuraminidase S.

The intrinsically disordered C-terminal domain (CTD) of protein 4.1G is able to specifically bind a 26-residue intrinsically disordered region of NuMA, forming a dynamic fuzzy complex. As one of a few cases of extremely fuzzy interactions between two intrinsically disordered proteins/regions (IDPs/IDRs) without induced folding, the principle of the binding is unknown. Here, we combined experimental and computational methods to explore the detailed mechanism of the interaction between 4.1G-CTD and NuMA. MD simulations suggest that the kinetic hub states in the structure ensemble of 4.1G-CTD are favorable in the fuzzy complex. The feature of these hub states is that the binding 'hot spot' motifs βA and βB exhibit β strand propensities and are well packed to each other. The binding between 4.1G-CTD and NuMA is disrupted at low pH, which changes the intramolecular packing of 4.1G-CTD and weakens the packing between βA and βB motifs. Low pH conditions also lead to increased hydrodynamic radius and acceleration of backbone dynamics of 4.1G-CTD. All these results underscore the importance of tertiary structural arrangements and overall compactness of 4.1G-CTD in its binding to NuMA

Biological desulfurization offers several remarkably environmental advantages of operation at ambient temperature and atmospheric pressure, no demand of toxic chemicals as well as the formation of biologically re‐usable sulfur (S0), which has attracted increasing attention compared to conventionally physicochemical approaches in removing hydrogen sulfide from sour gas. However, the low biomass of SOB, the acidification of process solution, the recovery of SOB, and the selectivity of bio‐S0 limit its industrial application. Therefore, more efforts should be made in the improvement of the BDS process for its industrial application via different research perspectives. This review summarized the recent research advances in the microbial capture of hydrogen sulfide from sour gas based on strain modification, absorption enhancement, and bioreactor modification. Several efficient solutions to limitations for the BDS process were proposed, which paved the way for the future development of BDS industrialization.

In this article, we show that the conventional boron-nitrogen co-doped carbon dots (BNCDs) exhibit unique fluorescent ratiometricity in the detection of Cr (VI) due to their unique dual emission system. The 3D fluorescence spectrum study reveals that besides the commonplace emission centered at (360, 465) nm in blue fluorescence region, another center which may be corresponding to N-contain conjugation domains is found at (490, 535) nm. In the presence of Cr (VI) ions, the emission centered at (360, 465) nm is remarkably quenched due to inner filter effect, whereas the emission centered at (490, 535) nm is almost unchanged. By spectrally simulating inner filter effect using different excitation interferents in the 3D fluorescence spectrum study, accompanied with the fluorescence lifetime and absorption comparison, the sensing mechanism has thoroughly been illustrated. The versatile sensing capability of BNCDs in the different real samples not only provides a new way for the rapid determination of Cr (VI) in practices, but also demonstrates the great potential of the carbon-based materials with multiple emission possess in developing ratiometric sensing platform for rapid and accurate assay of different kinds of analytes.

Evaluating the binding free energy of the protein-ligand complex is one of the most important tasks in drug design. Compared to methods like free energy perturbation (FEP) and thermodynamic integration (TI) which are accurate but resource expensive, and docking scoring functions which are less reliable but efficient, molecular mechanics/Generalized-Born (Poisson–Boltzmann) surface area (MM/GB(PB)SA), which balance accuracy and efficiency, is a good choice for evaluating binding free energy in virtual screening. There are several open-source tools for performing MM/GB(PB)SA calculations, but they are not easy to use, especially when processing a large number of molecules. Here we introduce Uni-GBSA, an automatic workflow to perform MM/GB(PB)SA calculations from force field building, structure optimization to free energy calculation. For evaluating several molecules against one protein target in virtual screening, Uni-GBSA offers a batch mode, eliminating many repeated calculations, to process the calculation for multi-molecules simultaneously and efficiently. Experiments show that Uni-GBSA with carefully designed default settings of parameters and workflow can obtain reliable binding free energy evaluation. Uni-GBSA software, including source code, is free and available at https://github.com/dptech-corp/Uni-GBSA.

The haloalkaliphilic genus Thioalkalivibrio, widely used in bio-desulfurization, can oxidize H

We developed a voltage-sensitive artificial transmembrane channel by mimicking the dipolar structure of natural alamethicin channel. The artificial channel featured a zwitterionic structure and could undergo voltage-driven flipping in the lipid bilayers. Importantly, this flipping of the channel could lead to their directional alignment in the bilayers and rectifying behavior for ion transport.

BACKGROUND d-Lactic acid (d-LA) is gaining increased attention as it can be applied in the food, pharmaceutical, cosmetic, polylactic acid and textile industries. Acid-tolerant Saccharomyces cerevisiae is often engineered to produce organic acids. For the pyruvate decarboxylases (PDCs) or alcohol dehydrogenase 1 (ADH1) disrupted strains, the productivity of d-LA significantly decreases due to the accumulation of acetaldehyde and acetic acid. To overcome the problem, Escherichia coli acetylating acetaldehyde dehydrogenase (A-ALD) enzyme genes (MHPF and EUTE) (EC 1.2.1.10) were integrated into the d-LA producing strain YIP-A15G12 strain (CGMCC2.5803). The function of these genes is to directly convert acetaldehyde into acetyl-CoA without energy consumption. This strain was integrated with Escherichia coli d-lactate dehydrogenase and Issatchenkia orientalis glycosylphosphatidylinositol-anchored protein IoGas1gene and several attenuated key pathway genes, including PDC1, PDC6, ADH1, ADH5, JEN1 (a monocarboxylate transporter), d-lactate dehydrogenase 1 (DLD1), l-lactate cytochrome c oxidoreductase (CYB2) and glycerol-3-phosphate dehydrogenases (GPD1, GPD2). RESULTS The strain expressions of the A-ALD enzymes effectively complemented the attenuated acetaldehyde dehydrogenase (ALD) acetyl-CoA synthetase (ACS) pathway and significantly improved the levels of acetyl-CoA and the productivity of d-LA. Finally, the resulting strainYIP-m-ald6 (CGMCC2.5826) produced 86.9 g L-1 d-LA with a yield of 0.77 g g(-1) glucose and a volumetric productivity of 1.77 g L-1 h(-1) at pH 3.58 under fed-batch fermentation conditions. CONCLUSION Introducing the E. coli acetyl-CoA synthesis pathway into the yeast strain can significantly enhance the growth of the strain and improve the d-LA productivity, as a benefit for d-LA production in industry. (c) 2021 Society of Chemical Industry (SCI).

The d-glucose/d-galactose-binding protein (GGBP) from Escherichia coli is a substrate-binding protein (SBP) associated with sugar transport and chemotaxis. It is also a calcium-binding protein, which makes it unique in the SBP family. However, the functional importance of Ca2+ binding is not fully understood. Here, the calcium-dependent properties of GGBP were explored by all-atom molecular dynamics simulations and Markov state model (MSM) analysis as well as single-molecule Forster resonance energy transfer (smFRET) measurements. In agreement with previous experimental studies, we observed the structure stabilization effect of Ca2+ binding on the C-terminal domain of GGBP, especially the Ca2+-binding site. Interestingly, the MSMs of calcium-depleted GGBP and calcium-bound GGBP (GGBP/Ca2+) demonstrate that Ca2+ greatly stabilizes the open conformation, and smFRET measurements confirmed this result. Further analysis reveals that Ca2+ binding disturbs the local hydrogen bonding interactions and the conformational dynamics of the hinge region, thereby weakening the long-range interdomain correlations to favor the open conformation. These results suggest an active regulatory role of Ca2+ binding in GGBP, which finely tunes the conformational distribution. The work sheds new light on the study of calcium-binding proteins in prokaryotes.

Sulfide from anaerobic treatment of high-sulfate wastewater would always have some adverse effects on downstream processes. In this study, a coupling anaerobic/aerobic system was developed and operated under haloalkaliphilic condition to realize deep and high-efficiency removal of sulfate without production of sulfide. A haloalkaliphilic sulfur-oxidizing strain, Thioalkalivibrio versutus SOB306, was responsible for oxidation of sulfide. The anaerobic part was first operated at optimum condition based on a previous study. Then, its effluent with an average sulfide concentration of 674 ± 33 mg·l−1 was further directly treated by a set of 1 l biofilter with SOB306 strain under aerobic condition. Finally, 100% removal rate of sulfide was achieved at aeration rate of 0.75 l·l−1·min−1, ORP of − 392 mV and HRT of 4 h. The average yield of elemental sulfur reached 79.1 ± 1.3% in the filter, and the CROS achieved a conversion rate of sulfate to sulfur beyond 54%. This study for the first time revealed the characteristics and performance of the haloalkaliphilic CROS in deep treatment of high-sulfate wastewater, which paved the way for the development and application of this method in the real world.

We investigated the biosynthetic pathway of type II polyketide murayaquinone. The murayaquinone biosynthetic cluster contains genes for three putative short-chain dehydrogenase/reductase family enzymes including MrqF and MrqH with known functions and MrqM with unclear function. We report the functional characterization of MrqM for its role in murayaquinone biosynthesis. Our gene deletion experiment and structural elucidation of the accumulated intermediates revealed that MrqM is related with the second polyketide ring cyclization, because the inactivation of mrqM resulted in the accumulation of an off-pathway intermediate SEK43 and disrupted the second and third ring cyclization. Site-directed mutagenesis studies showed that two conserved residues in MrqM and homologous proteins Y151 and K155 are essential for its activity. The previously proposed second/third ring cyclase, MrqD, might instead play another important role in the chain releasing step of the murayaquinone biosynthesis.

Bacteria are important participants in sulfur cycle of the extremely haloalkaline environment, e.g. soda lakes. The effects of physicochemical factors on the composition of sulfide-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) in soda lakes have remained elusive. Here, we surveyed the communities structure of total bacteria, SOB and SRB based on 16S rRNA, soxB and dsrB gene sequencing, respectively, in five soda lakes with different physicochemical factors. The results showed that the dominant bacteria in soda lakes sediments belonged to the phyla Proteobacteria, Bacteroidetes, Halanaerobiaeota, Firmicutes and Actinobacteria. SOB and SRB were widely distributed in lakes with different physicochemical characteristics，and the community composition were different . In general, salinity and inorganic nitrogen sources (NH4+-N, NO3--N) were the most significant factors. Specifically, the communities of SOB, mainly including Thioalkalivibrio, Burkholderia, Paracoccus, Bradyrhizobium, and Hydrogenophaga genera, were remarkably influenced by the levels of NH4+-N and salinity. Yet, for SRB communities, including Desulfurivibrio, Candidatus Electrothrix, Desulfonatronospira, Desulfonatronum, Desulfonatronovibrio, Desulfonatronobacter and so on, the most significant determinants were salinity and NO3--N. Besides, Rhodoplanes played a significant role in the interaction between SOB and SRB. From our results, the knowledge regarding the community structures of SOB and SRB in extremely haloalkaline environment was extended.

American ginseng and Asian ginseng products have similar appearance, however, the huge price differences for various species and grades of ginseng lead to the widespread adulteration in the commercial market. We herein reported an efficient colorimetric sensor array for ginseng discrimination through analysis of diols composition (e.g. monosaccharide and ginsenoside). The sensor array was rationally designed based on two mechanisms, changes in pH and indicators displacement assay (IDA), with phenylboronic acid as the receptor to diols. The excellent discrimination capability of the sensor array was validated upon analysis of different species or concentrations of monosaccharides in ginseng hydrolysate. 40 ginseng samples within three categories (cultivated American ginseng, wild American ginseng and Asian ginseng) were successfully classified using the sensor array coupled with a statistical analysis such as hierarchy cluster analysis (HCA) and principal component analysis (PCA). Our work provided a simple and effective method for the fast discrimination and quality control of ginseng products.

Efficient removal of high concentration sulfate from wastewater with high sodium concentration and pH is a challenge to date. In this study, a bench-scale haloalkaliphilic bioreactor was continuously operated for high-efficiency treatment of high concentration sulfate in simulation wastewater. It was found that up to 70% of sulfate was removed within hydranlic retention time of 24 h when sulfate concentration in influent was as high as 3000 mgl−1 at 1.0 M Na+ and pH 9.5. Sulfate removal rate reached 2.12 gl−1d−1, which was much higher than results in literatures. The bottom region of bioreactor contributed approximate sulfate removal of 40% to total sulfate reduction. Then, the rate decreased gradually with the reduction of depth. Moreover, the composition of organic acids was closely related to depth of the bioreactor. According to microbial community analysis, Desulfonatronovibrio might play the most important role in sulfate removal, and its relative abundance was the highest at bottom region. The abundance decreased gradually as reduction of the depth of bioreactor. In addition, these results revealed a dynamic process of sulfate removal and variety of bacterial communities in whole bioreactor. The identification of many microorganisms by 16S rRNA sequencing deepened the insight of SRB interaction with non-SRB in sulfate-removal process. The high-efficiency process offered a great biotechnological penitential for sulfate removal of industrial wastewater.

D-lactic acid (D-LA) is gaining increased attention as it can improve the thermostability of poly lactic acid. Acid-tolerant Saccharomyces cerevisiae is a good host for D-LA fermentation. High catalytic efficiency of D-lactate dehydrogenase (D-LDH, EC 1.1.1.28) is crucial for the production of D-LA in yeast. Here, a synthetic biology approach was used to construct high-producing D-LA strains by redesigning and optimization of D-LDH expression by a combination of different promoters, terminators and D-LDHs. The pyruvate decarboxylase-deficient mutant strain TAMH was used as host strain for optimizing the 40 D-LDH expression cassettes. The TCSt strain harboring the pTCSt plasmid with the TEF1 promoter, E. coli D-LDH and Synth25 synthetic short terminator produced 5.8 g/L D-LA with an optical purity of 99.9%. The production of D-LA was further improved by integrating this high expression cassette into the Ty1 transposable element of the YIP-01 strain with deleted Pdc1and Pdc6. The resulting strain YIP-pTCSt-301(CGMCC2.5726) was screened by a double enzyme-coupled system. Genomes sequencing of the strain revealed three copies of the D-LDH expression cassette. This strain was further improved by deleting the Jen1, Cyb2, Dld1, and Adh1 genes and the resulting strain YIP-J-C-D-A1 (CGMCC2.5783) produced 80.0 g/L D-LA with a yield of 0.6 g/g glucose and a volumetric productivity of 1.1 g/L/h in fed-batch fermentation under non-neutralization conditions.

Succinic acid is a spectacular chemical that can be used as the precursor of various industrial products including pharmaceuticals and biochemicals. The improvement of the succinic acid market depends on strains engineering that is capable of producing succinic acid at high yield and excellent growth rate which could utilize the wide range of carbon sources such as renewable biomass. Here we use counter selection using catAsacB for pathway design and strains developments. In this investigation, metabolically engineered Escherichia coli M6PM strain was constructed for the synthesis of succinic acid using elephant grass stalk (Pennisetum purpureum) as a carbon source. Elephant grass stalk hydrolysate was prepared which comprised of 11.60 ± 0.04 g/L glucose, 27.22 ± 0.04 g/L xylose and 0.65 ± 0.04 g/L arabinose. Metabolically engineered E. coli M6PM was constructed and fermentation with pure sugars revealed that it could utilize xylose and glucose efficiently. E. coli M6PM produced a final succinate concentration of 30.03 ± 0.02 g/L and a yield of 1.09 mol/mol during 72 h dual-phase fermentation using elephant grass stalk hydrolysate, which resulted in 64% maximum theoretical yield of succinic acid. The high succinate yield from elephant grass stalk demonstrated possible application of renewable biomass as feedstock for the synthesis of succinic acid using recombinant E. coli.

Haloalkaliphilic Thioalkalivibrio, a dominant genus for sulfide removal, has attracted growing interest. However, the bacterial biological response to this process’s final product, sulfate, has not been well-studied. Here, thiosulfate oxidation and sulfur formation by T. versutus D301 were being enhanced with increasing sulfate supply. With the addition of 0.73 M sulfate, the thiosulfate utilization rate and sulfur production were improved by 68.1% and 120.1% compared with carbonate-grown control at the same salinity (1.8 M). For sulfate-grown cells, based on metabolic analysis, the downregulation of central carbon metabolism indicated that sulfate triggered a decrease in energy conservation efficiency. Additionally, the gene expression analysis further revealed that sulfate induced the inhibition of sulfur to sulfate oxidation, causing the upregulation of thiosulfate to sulfur oxidation for providing cells with additional energy. This study enhances researchers’ understanding regarding the sulfate effect on the bio-desulfurization process and presents a new perspective of optimizing the biotechniques.

As a green and economic emerging technology, biological desulfurization is popular. However, biological desulfurization is inhibited by organosulfur in the treatment gases which cannot be ignored. This article summarizes relevant studies on the influence of organosulfur on biological desulfurization in recent years, including the types and physicochemical characteristics of organosulfur, the influence of organosulfur on the desulfurization process, the reaction mechanism of organosulfur, the interplay between organosulfur and some operating conditions, and species of microorganisms that are tolerant to organosulfur. Methods for mitigating the effect of organosulfur on the desulfurization process are discussed, to provide references for the stable and efficient operation of biological desulfurization.作为一种绿色、经济的新兴技术，生物脱硫技术正逐渐受到人们的青睐。然而，处理气体中的有机硫对生物脱硫过程的抑制是一个不容忽视的问题。文中总结了近年来国际上对生物脱硫过程中有机硫影响的相关研究，主要包括有机硫的种类及理化特征、有机硫对脱硫过程的影响、有机硫的作用机理、操作条件与有机硫的相互关系以及耐受有机硫微生物的种类，并据此归纳了缓解有机硫对脱硫过程影响的一些方法，为生物脱硫工艺在实际应用中稳定、高效地运行提供一定的指导。.

Self-assembly is ubiquitous in the realm of biology and has become an elegant bottom-up approach to fabricate new materials. Although molecular dynamics (MD) simulations can complement experiments by providing the missing atomic details, it still remains a grand challenge to reveal the thermodynamic and kinetic information on a self-assembly system. In this work, we demonstrate for the first time that the Markov state model analysis can be used to delineate the variation of free energy during the self-assembly process of a typical amphiphilic lipid dipalmitoyl-phosphatidylcholine (DPPC). Free energy profiles against the solvent-accessible surface area and the root-mean-square deviation have been derived from extensive MD results of more than five hundred trajectories, which identified a metastable crossing-cylinder (CC) state and a transition state of the distorted bilayer with a free energy barrier of ∼0.02 kJ mol-1 per DPPC lipid, clarifying a long-standing speculation for 20 years that there exists a free energy barrier during lipid self-assembly. Our simulations also unearth two mesophase structures at the early stage of self-assembly, discovering two assembling pathways to the CC state that have never been reported before. Further thermodynamic analysis derives the contributions from the enthalpy and the entropy terms to the free energy, demonstrating the critical role played by the enthalpy-entropy compensation. Our strategy opens the door to quantitatively understand the self-assembly processes in general and provides new opportunities for identifying common thermodynamic and kinetic patterns in different self-assembly systems and inspiring new ideas for experiments. It may also contribute to the refinement of force field parameters of various self-assembly systems.

Naringenin (NAR) is a natural flavonoid which exerts extensive biological activity, including anti-oxidation, anti-inflammation, anti-cancer, immune regulation and so on. However, the effect and mechanism of NAR in the alveolar bone regeneration are still unclear, which limits its clinical use. Hence, we investigated the effects of NAR in the proliferation, osteogenic and endothelial differentiation of human periodontal ligament stem cells (hPDLSCs) and explore the possible mechanism. The results showed that the proper concentrations (100 nM–10 μM) of NAR can promote the proliferation rate, osteogenic and endothelial differentiation of hPDLSCs. And the 1 μM NAR had the best proliferation promoting effect, while the 10 μM NAR had the best ability of promoting osteogenic and endothelial differentiation. NAR also promoted the mRNA expression of SDF-1 in a concentration dependent manner in PDLSCs. After adding the selective CXCR4 antagonist AMD3100, the osteogenic effect of NAR on PDLSCs is slightly enhanced, while the endothelial differentiation effect of NAR on hPDLSCs is attenuated. In summary, these results indicated that NAR promoted the proliferation of hPDLSCs, and promoted endothelial differentiation of hPDLSCs via SDF-1 to activate SDF-1/CXCR4 signaling pathway. However, the mechanism of which SDF-1 related signaling pathway is activated by NAR to enhance the osteogenic differentiation of hPDLSCs still needs to be investigated.

Biological desulfurization is a process in which sulfur compounds are removed from gas and oil using microorganisms. It is a simple process that has mild operating conditions, high desulfurization efficiency, low energy consumption and less environmental pollution. However, there is still a lack of simple and efficient analytical methods for quantitatively analyzing the sulfur compounds in the biological desulfurization process. In order to solve this problem, the analytical method for the simultaneous determination of sulfite, thiosulfate and sulfide in biological desulfurization solutions by pre-column fluorescence derivation using high performance liquid chromatography (HPLC) was developed. The standard curves of sulfur species in this analytical method had good linear relationships with correlation coefficients of 0.999 5, 0.999 7, and 0.999 7 for sulfite, thiosulfate and sulfide, respectively. The detection limits of these sulfur compounds were 0.000 6, 0.000 7 and 0.001 1 μmol/L; the range of recovery rates were 98.17 to 101.9%, 100.9 to 102.6%, and 101.1 to 104.2%; which had good repeatability and stability. The analytical method was simple, efficient and accurate, and could be used to simultaneously determine the sulfur compounds in different biological desulfurization systems.生物脱硫是利用微生物脱除气体和石油中的含硫化合物，具有操作条件温和、工艺流程简单、脱硫效率高、能量消耗低和环境污染少等优点。但是，当前仍然缺乏简单高效的分析方法来定量分析生物脱硫过程中的含硫化合物。针对这个问题，建立了柱前荧光衍生高效液相色谱法同时测定生物脱硫溶液中的亚硫酸盐、硫代硫酸盐和硫化物的分析方法。该分析方法中含硫化合物的标准曲线具有良好的线性关系，亚硫酸盐、硫代硫酸盐和硫化物相关系数分别为0.999 46、0.999 67 和0.999 65，其检测限分别为0.000 6 μmol/L、0.000 7 μmol/L 和0.001 1 μmol/L；含硫化合物的加标回收率范围分别为98.17%–101.92%、100.90%–102.60%和101.11%–104.22%；并具有良好的重复性和稳定性。实验证明，该分析方法预处理简单、分析快速、结果准确，可用于同时测定不同生物脱硫系统中的含硫化合物。.

The genus Thialkalivibrio plays an essential role in the biological desulfurization system. However, to date, the sulfur oxidation pathways of Thialkalivibrio are not clearly understood. Here, we performed transcriptomic analysis on Thialkalivibrio versutus D301 with either thiosulfate or chemical sulfur as the sulfur source to understand it. The results show that T. versutus D301 has a higher growth rate and sulfur oxidation activity when thiosulfate is utilized. The use of chemical sulfur as sulfur source leads to decreased expression of genes involved in carbon metabolism, ribosome synthesis and oxidative phosphorylation in T. versutus D301. Potentially due to the adsorption to sulfur particles, the genes related to flagellum assembly and motivation are significantly induced in T. versutus D301 in the presence of chemical sulfur. In the periplasm, both thiosulfate and polysulfide from the chemical sulfur are oxidized to sulfate via the similar truncated Sox system (SoxAXYZB). Then, part of polysulfide reached to cytoplasm through an unidentified route is oxidized to sulfite by the Dsr-like system. The sulfite in the cytoplasm is further catalyzed to sulfate by SoxB or SoeABC. Overall, the difference in the oxidation rates of D301 can be mainly attributed to the bioavailability of the two sulfur sources, not the sulfur oxidation pathways.

Complicated production procedures and superior characteristics of nano-sized sulfur elevate its price to 25–40 fold higher than micrograde kind. Also, natural gas hydrogen sulfide levels are restricted because of its toxic environmental consequences. Thioalkalivibrio versutus is a polyextremophilic industrial autotroph with high natural gas desulfurization capability. Here, nanometric (>50 nm) sulfur bioproduction using T. versutus while desulfurizing natural gas was validated. Also, this production was enhanced by 166.7% via lowering sulfate production by 55.1%. A specially-developed CRISPR system, with 42% editing efficiency, simplified the genome editing workflow scheme for this challenging bacterium. In parallel, sulfur metabolism was uncovered using proteins mining and transcriptome studies for defining sulfate-producing key genes (heterodisulfide reductase-like complex, sulfur dioxygenase, sulfite dehydrogenase and sulfite oxidase). This study provided cost-effective nanometric sulfur production and improved this production using a novel CRISPR strategy, which could be suitable for industrial polyextremophiles, after uncovering sulfur pathways in T. versutus.

A biorefinery process for high yield production of succinic acid from biomass sugars was investigated using recombinant Escherichia coli. The major problem been addressed is utilization of waste biomass for the production of succinic acid using metabolic engineering strategy. Here, methanol extract of Strophanthus preussii was used for fermentation. The process parameters were optimized. Glucose (9 g/L), galactose (4 g/L), xylose (6 g/L) and arabinose (0.5 g/L) were the major sugars present in the methanol extract of S. preussii. E. coli K3OS with overexpression of soluble nucleotide pyridine transhydrogenase sthA and mutation of lactate dehydrogenase A (ldhA), phosphotransacetylase acetate kinase A (pta-ackA), pyruvate formate lyase B (pflB), pyruvate oxidase B (poxB), produced a final succinic acid concentration of 14.40 g/L and yield of 1.10 mol/mol total sugars after 72 h dual-phase fermentation in M9 medium. Here, we show that the maximum theoretical yield using methanol extracts of S. preussii was 64%. Hence, methanol extract of S. preussii could be used for the production of biochemicals such as succinate, malate and pyruvate.

Due to the decrease of intracellular NADH availability, gluconate metabolism is more conducive to pyruvate production than glucose. Transcriptome analysis revealed that the Entner–Doudoroff (ED) pathway was activated by gluconate in Escherichia coli YP211 (MG1655 Δ ldhA Δ pflB Δ pta-ackA Δ poxB Δ ppc Δ frdBC ). To construct a new pyruvate producing strain with glucose metabolism via ED pathway, the genes ppsA , ptsG , pgi and gnd were deleted sequentially to reduce the demand for PEP and block the Embden–Meyerhor–Parnas pathway and Pentose-Phosphate pathway. After nearly 1000 generations of growth-based selection, the evolved strain YP404 was isolated and the ED pathway was proved to be activated as the primary glycolytic pathway. Comparing with YP211, the pyruvate concentration and yield increased by 59% and 10.1%, respectively. In fed-batch fermentation, the pyruvate concentration reached 83.5 g l −1 with a volumetric productivity of 2.3 g l −1 h −1 . This was the first time to produce pyruvate via ED pathway, and prove that this was a more effective way.