Seroprevalence of Epizootic Hemorrhagic Disease Virus in Guangdong Cattle Farms during 2013-2017, China.

Epizootic hemorrhagic disease (EHD) is an infectious viral disease caused by epizootic hemorrhagic disease virus (EHDV) and EHDV frequently circulates in wild and domestic ruminants. Sporadic outbreaks of EHD have caused thousands of deaths and stillbirths on cattle farms. However, not much is known about the circulating status of EHDV in Guangdong, southern China. To estimate the seroprevalence of EHDV in Guangdong province, 2886 cattle serum samples were collected from 2013 to 2017 and tested for antibodies against EHDV using a competitive ELISA. The overall seroprevalence of EHDV reached 57.87% and was highest in autumn (75.34%). A subset of positive samples were serotyped by a serum neutralization test, showing that EHDV serotypes 1 and 5-8 were circulating in Guangdong. In addition, EHDV prevalence always peaked in autumn, while eastern Guangdong had the highest EHDV seropositivity over the five-year period, displaying apparent temporal-spatial distribution of EHDV prevalence. A binary logistic model analysis indicated a significant association between cattle with BTV infections and seroprevalence of EHDV (OR = 1.70, p < 0.001). The co-infection of different serotypes of EHDV and BTV raises a high risk of potential genomic reassortment and is likely to pose a significant threat to cattle, thus urging more surveillance to monitor their circulating dynamics in China.

Isolation and Genetic Evolution of Dengue Virus from the 2019 Outbreak in Xishuangbanna, Yunnan Province, China.

Background: Dengue virus (DENV) can be divided into four serotypes-DENV-1, DENV-2, DENV-3, and DENV-4. In humans, infection leads to dengue fever (DF), dengue hemorrhagic fever, and dengue shock syndrome, both widely prevalent in tropical and subtropical regions. In 2019, a severe outbreak of DF occurred in Xishuangbanna, Yunnan province. Objective: To investigate the etiology and genotype of the causative agents of this severe dengue outbreak in Xishuangbanna. Methods: Between October and November 2019, the sera of patients clinically diagnosed with DF were collected in the first People's Hospital of Xishuangbanna. RNA was extracted from the sera and amplified by RT-PCR with flavivirus primers. Flavivirus-positive sera were then used to inoculate Aedes albopictus cells (C6/36); viral RNA was extracted from these cells, amplified, and sequenced with DENV E gene-specific primers. Sequence splicing and nucleotide homology genetic evolution analysis were carried out by biological software (DNAStar). Unique mutations in the E genes of isolated DENV were analyzed by SWISS-MODEL and PyMOL. Results: Of the 60 samples collected from DF patients, 39 tested positively with flavivirus primers. The DENV was isolated from 25 of the 39 positive seras, of which 20 showed cytopathic effects (CPE) and 5 were no CPE. In these 25 isolated nucleic acids, 21 strains of DENV-1, 3 strains of DENV-2, and 1 strain of DENV-3 were identified according to the sequence of E protein. In the four unique mutations (D52, Y149, L312, T386), D52 and Y149 in the E protein of DENV-1 were predicted to be exposed on the surface of the prefusion conformation. Conclusion: The 2019 outbreak of DF in Xishuangbanna area of Yunnan Province consists of at least three serotypes of DENV-1, DENV-2, and DENV-3, and the sources of these virus strains are of mixed and complicated origin.

[Effects of 24 Years Different Straw Return on Soil Carbon, Nitrogen, Phosphorus, and Extracellular Enzymatic Stoichiometry in Dryland of the Loess Plateau, China].

Exploring the biogeochemical cycle characteristics of soil carbon, nitrogen, and phosphorus in farmland in the dryland of the loess plateau can provide scientific basis and technical support for efficient crop production and sustainable land use. Here, based on a long-term (24 year) straw return field experiment in Shouyang, Shanxi province, the effects of different straw return regimes, i.e., straw mulching (SM), direct straw return (DS), animal-digested straw return (AS), and non-straw return (CK), on the stoichiometric ratio of soil elements and extracellular enzyme activities were studied. The vector angle and length were calculated to indicate the resource constraints faced by microorganisms. The vector angle was greater than 45° and less than 45°, indicating that microorganisms were limited by phosphorus and nitrogen, respectively. The greater the deviation from 45°, the greater the degree of limitation, and the longer the vector length, the more severely limited by carbon. The results showed that ① the soil C/N and C/P of long-term straw returning ranged from 9.81 to 14.28 and from 14.58 to 21.92, with the mean values of 12.36 and 17.51, respectively, which were 6.0% and 4.2% lower than that at the initial stage of the experiment. The soil N/P was distributed between 1.27 and 1.57, with an average of 1.42, which was 2.2% higher than that in the initial stage. The soil C/N and C/P ratios showed a trend of first decreasing and then increasing, the soil N/P ratio basically showed a flat trend, and there was no significant difference in soil element metering ratios between different straw returning treatments. ② Compared with the 24-year long-term non-straw return treatment, the activities of ß-1,4-glucosidase (BG) and ß-1,4-N-acetylglucosaminidase (NAG) in the soil of the long-term straw mulching treatment increased by 134.4% and 107.5% (P<0.05), the activities of BG and alkaline phosphatase (AP) in the soil of the long-term straw mulching treatment decreased by 59.3% and 59.5% (P<0.05), respectively, and the activities of NAG in the soil of the long-term straw mulching treatment increased by 102.8% (P<0.05). Under the long-term straw returning treatment, soil microorganisms were faced with carbon and phosphorus limitation as a whole. Long-term straw mulching aggravated microbial carbon limitation, and animal-digested straw return could alleviate the degree of carbon limitation. Compared with that in the 24-year long-term non-straw return treatment, soil EEAC/N could be significantly reduced by the animal-digested straw return treatment, and soil EEAC/P could be increased by the direct straw return treatment. The three straw returning methods had no significant indigenous effect on soil EEAN/P. The overall vector angle was greater than 45°, and the vector length increased by 3.8%-20.1% compared with that in the initial stage. ③ Correlation analysis showed that C and N inputs were significantly negatively correlated with BG activity; available nitrogen was significantly correlated with NAG activity, AP activity, and EEAC/N; C/P was significantly positively correlated with EEAC/N; there were significant correlations between N/P and NAG activity, AP activity, EEAC/N, and EEAC/P; and there was no significant correlation between EEAN/P and any environmental factors. In conclusion, the availability of soil nitrogen and phosphorus elements and N/P ratio had significant effects on soil extracellular enzyme activity and stoichiometric characteristics under different long-term straw returning treatments. In the future, more attention should be paid to the improvement of organic carbon and the promotion of nitrogen and phosphorus availability in farmland soil in soil-efficient cultivation and agricultural production activities.

Two putative novel serotypes of Tibet orbivirus isolated from Culicoides spp. in Yunnan, China.

Tibet orbivirus (TIBOV) was identified as a novel orbivirus in 2014. Antibodies against TIBOV were detected in cattle, Asian buffalo, and goats, while all the sequenced TIBOV strains were isolated from mosquitos and Culicoides. The known TIBOV strains have been classified into four putative serotypes. In this study, two TIBOV strains isolated from Culicoides spp. in Shizong County of Yunnan Province, China, were fully sequenced. The phylogenetic analysis of outer capsid protein 2 (VP2) indicated that these two viral strains belong to two novel putative serotypes of TIBOV. The updated putative serotypes may help in an investigation of the distribution and virulence of TIBOV.

Synthesis and evaluation of Mn-Sn modified Ru-Ir electrode for electrocatalytic treatment of high chloride acrylonitrile wastewater.

Acrylonitrile wastewater was an organic wastewater with strong toxicity and poor biodegradability. Therefore, electro-catalytic technology became a promising acrylonitrile wastewater treatment technology because of no secondary pollution, wide application range and low water quality requirements. The optimal Mn-Sn modified Ru-Ir electrode material was synthesized by thermal method and applied in electro-catalytic treatment of acrylonitrile wastewater. The electrode materials were characterized by SEM, TEM, XRD, XPS and electrochemical characterization. SEM, TEM, XRD and XPS indicated that Mn and Sn were capable of incorporating and replacing the part of Ru or Ir and could alter the microstructure of Ru-Ir and the types of Mn and Sn oxides, raising the oxygen evolution potential (OEP) and voltampere charge. When the molar ratio of Mn-Sn was 1:1, OEP, voltampere charge and exchange current density could reach 1.303 V, 1.51 C/cm2 and 6.29×10-4 A/cm2, respectively. The co-doping of Mn-Sn had significant influence on the electrocatalytic performance of Ru-Ir electrode materials. The optimum synthesis conditions of Mn-Sn modified Ru-Ir electrode were as follows: the molar ratio of Mn-Sn was 1:1, calcination time was 4.0 hours, calcination temperature was 450℃, and solvent was water. Under certain conditions, the removal rate of acrylonitrile with Mn-Sn modified Ru-Ir electrode was 100%. Mn-Sn modified Ru-Ir electrode had high oxygen evolution potential and good removal effect of acrylonitrile, which was higher than that of ruthenium iridium electrode and RuO2 electrode.

Application of Pd-Sn modified Ru-Ir electrode for treating high chlorine ammonia-nitrogen wastewater.

Electro-catalytic technology is a promising approach for wastewater treatment, owing to its easy operation, minimal generation of secondary pollution, small foot-print and rapid start-up. In this work, the chlorine evolution potential of the Pd-Sn modified ruthenium(Ru)-iridium(Ir) electrode was investigated for the electro-catalytic treatment of high chlorine ammonia-nitrogen wastewater. The effect of reaction conditions on the removal of ammonia-nitrogen, kinetics and apparent activation energy of ammonia-nitrogen removal were studied. The possible denitrification process of high chlorine ammonia-nitrogen wastewater was discussed. The results indicated that the chlorine evolution potential of the Pd-Sn modified Ru-Ir electrode was 1.0956 V(vs. SCE). The electro-catalytic treatment of high chlorine ammonia-nitrogen conformed to zero-order kinetic law, and the apparent activation energy of removal process was 14.089 kJ/mol. With a current was 0.5 A, the removal efficiency of ammonia-nitrogen could achieve 100% at a reaction time of 40 min. Indirect oxidation played an essential role in the electro-catalytic ammonia-nitrogen removal using the Pd-Sn modified Ru-Ir electrode. This paper demonstrated that the electro-catalytic technology was a promising approach for efficiently treating the high chlorine ammonia-nitrogen wastewater.

Genetic and Pathogenic Characterisation of a Virulent Akabane Virus Isolated from Goats in Yunnan, China.

Introduction: Akabane virus (AKAV) has been detected in a variety of host species in China, but there are only limited records of its occurrence in goats. However, more attention needs to be paid to understanding the diversity of viruses in this species. The aim of the study was to explore the genotype characteristics and variation trend of AKAV and their relationship with virulence in Yunnan, China. Material and Methods: Blood samples were collected from goats during routine surveillance of goat diseases in Yunnan province in 2019. The AKAV CX-01 strain was isolated using BHK-21 cells. To understand pathogenicity, the virus was intraperitoneally (IP) and intracerebrally (IC) inoculated into suckling mice and tissue samples were subsequently analysed histopathologically and immunohistochemically. Results: Akabane virus CX-01 strain induced encephalitis and impairment of the central nervous system with fatal consequences. Phylogenetic analysis based on the ORF sequences of the small segments indicated that the AKAV isolate used was most closely related to the GD18134/2018 Chinese midge and bovine NM BS/1strains, while phylogenetic analysis based on the medium segments showed a close relationship between CX-01 and the Chinese GLXCH01 strain. Conclusion: The CX-01 isolate was related to AKAV genogroup Ia and probably originated from a recombination of different strains.

Preparation and evaluation of Pd-Sn modified Ru-Ir electrode for denitrification of high chlorine ammonia-nitrogen wastewater.

In this paper, Pd-Sn modified Ru-Ir electrode was prepared by thermal oxidation method, and the effects of doping amount of Pd-Sn and synthesis conditions on Pd-Sn modified Ru-Ir electrode performance were studied. Linear sweep voltammetry(LSV), cyclic voltammetry(CV), and the Tafel curve were used to study the electrochemical performance of the Pd-Sn modified Ru-Ir electrode materials. The effects of the doping amount of Pd-Sn on the microstructure and valence states of Pd-Sn modified Ru-Ir electrode materials were investigated by SEM, TEM, XRD, and XPS. When the mass of Pd-Sn accounted for 1.5% of the total mass of the elements, the molar ratio of Ru-Ir was 2:1, and the molar ratio of Pd-Sn was 3:1; the LSV, CV, and the Tafel curves indicated that Pd-Sn modified Ru-Ir electrode had the lowest chlorine evolution potential (1.0640 V vs. SCE), the best CV curve coincidence, and the smallest corrosion current density (6.5 × 10-4 A/cm2), showing the best chlorine evolution performance, the best durability, and corrosion resistance; the characterization of SEM, TEM, XRD, and XPS showed that Pd-Sn was successfully doped into Ru-Ir electrode materials; the crystallinity of Pd-Sn modified Ru-Ir electrode was the highest, and the binding energy was the lowest, but the crystal form of Ru-Ir solid solution did not have changed. The optimal synthesis conditions of Pd-Sn modified Ru-Ir electrode material were as follows: Pd-Sn molar ratio was 3:1, calcination temperature was 500 ℃, calcination time was 4 h, and water was used as solvent. Pd-Sn modified Ru-Ir electrode can efficiently treat high chlorine ammonia-nitrogen wastewater, when the reaction volume was 200 mL, the initial concentration of NH3-N was 100 mg/L, the concentration of chloride ion was 5000 mg/L, the current was 0.75 A, and the reaction time was 40 min; the removal rate of ammonia nitrogen can reach 100%.Responsible editor: Weiming Zhang.

Efficacy and safety of humanized CD19 CAR-T as a salvage therapy for recurrent CNSL of B-ALL following murine CD19 CAR-T cell therapy.

The present study aimed to compare the differences between the humanized CD19 chimeric antigen receptor (CAR)-T cell therapy and the murine CD19 CAR-T therapy in recurrent B-acute lymphoblastic leukemia (B-ALL). A 62-year-old male patient who had B-ALL (BCR/ABL+) for 4 years was diagnosed with relapsed central nervous system leukemia (CNSL). After several courses of high dose methotrexate combined with intrathecal chemotherapy, the patient received murine CD19 CAR-T therapy and achieved complete response (CR). The patient was diagnosed with relapsed CNSL again 15 months after his murine CD19 CAR-T therapy, and was therefore enrolled in the humanized CD19 CAR-T therapy. Subsequently, the present study aimed to compare murine and humanized CD19 CAR-T cells against Nalm-6 cells in vitro and in mice. The patient initially achieved CR from his murine CD19 CAR-T therapy with Grade 1 cytokine-release syndrome (CRS) and Grade 1 CAR-T cell-related encephalopathy syndrome (CRES). The patient then achieved CR again from his humanized CD19 CAR-T therapy with Grade 1 CRS and Grade 2 CRES. Peak levels of CD19 CAR-T cells were higher in humanized CD19 CAR-T therapy than those in murine CD19 CAR-T therapy 7 days after infusion in the peripheral blood, in bone marrow and in cerebrospinal fluid (CSF). The cytokine levels were higher in humanized CD19 CAR-T therapy than those in murine CD19 CAR-T therapy in the peripheral blood and in CSF. The cytotoxicity to Nalm-6 cells was higher in humanized CD19 CAR-T cells than that in murine CD19 CAR-T cells in vitro. In Nalm-6 BALB/c mice, the median survival time of mice in the murine CD19 CAR-T group was 35 days, while it was 43 days in the humanized CD19 CAR-T group. In conclusion, humanized CD19 CAR-T cell therapy had a better curative effect than that of murine CD19 CAR-T therapy, and may be used as a salvage treatment for recurrent B-ALL after treatment with murine CD19 CAR-T therapy.

Isolation of Tibet Orbivirus from Culicoides jacobsoni (Diptera, Ceratopogonidae) in China.

BACKGROUND: Tibet Orbivirus (TIBOV) is a recently discovered Orbivirus known to infect cattle, Asian buffalo and goats in south-western China. It was first isolated from mosquitoes and subsequently from biting midges (Culicoides spp.) in Yunnan, China, indicating that it is an arbovirus. Little is known of its potential to cause disease, but the economic importance of related viruses promoted an investigation of potential Culicoides spp. vectors of TIBOV. METHODS: Biting midges were collected approximately once per week between May and December 2020, at a cattle farm in Wulong village, Shizong County, Yunnan Province, China. Approximately 3000 specimens of nine species were subsequently used in attempts to isolate virus, and a further 2000 specimens of six species were tested for the presence of bluetongue virus (BTV) and TIBOV using a RT-qPCR test. RESULTS: Virus isolation attempts resulted in the isolation of three viruses. One isolate from a pool of Culicoides jacobsoni was identified as TIBOV, while the other two viruses from C. orientalis and C. tainanus remain unidentified but are not BTV or TIBOV. RT-qPCR analysis did not detect BTV in any specimens, but a single pool containing five specimens of C. jacobsoni and another containing five specimens of C. tainanus produced PCR quantification cycle (Cq) values of around 28 that may indicate infection with TIBOV. CONCLUSIONS: The isolation of TIBOV from C. jacobsoni satisfies one criterion required to prove its status as a vector of this virus. This isolation is supported by a low Cq value produced from a different pool of this species in the RT-qPCR test. The low Cq value obtained from a pool of C. tainanus suggests that this species may also be able to satisfy this criterion. Both of these species are widespread throughout Asia, with C. jacobsoni extending into the Pacific region, which raises the possibility that TIBOV may be more widespread than is currently known.

Development and evaluation of recombinase polymerase amplification combined with lateral flow dipstick assays for co-detection of epizootic haemorrhagic disease virus and the Palyam serogroup virus.

BACKGROUND: Epizootic haemorrhagic disease virus (EHDV) and the Palyam serogroup viruses (PALV) have led to significant economic losses associated with livestock production globally. A rapid, sensitive and specific method for the detection of EHDV and PALV is critical for virus detection, monitoring, and successful control and elimination of related diseases. RESULTS: In the present study, a recombinase polymerase amplification combined with lateral flow dipstick (RPA-LFD) assay for the co-detection of genome segment 1 (Seg-1) of EHDV and PALV was developed and evaluated. The analytical sensitivities of the established RPA-LFD assay in the detection of EHDV and PALV were 7.1 copies/µL and 6.8 copies/µL, respectively. No cross-reaction with other members of the genus Orbivirus, including African horse sickness virus, bluetongue virus, Guangxi orbivirus, Tibet orbivirus and Yunnan orbivirus was observed. The established RPA-LFD assay accurately detected 39 EHDV strains belonging to 5 serotypes and 29 PALV strains belonging to 3 serotypes. The trace back results of quantitative real-time polymerase chain reaction (qRT-PCR) and the established RPA-LFD assay on sentinel cattle were consistent. The coincidence rates of qRT-PCR and the established RPA-LFD assay in 56 blood samples from which EHDV or PALV had been isolated and 96 blood samples collected from cattle farms were more than 94.8 %. The results demonstrated that the established RPR-LFD assay is specific, sensitive and reliable, and could be applied in early clinical diagnosis of EHDV and PALV. CONCLUSIONS: This study highlights the development and application of the RPA-LFD assay in the co-detection of EHDV and PALV for the first time. The assay could be used as a potential optional rapid, reliable, sensitive and low-cost method for field diagnosis of EHDV and PALV.

Detection of bluetongue virus in Culicoides spp. in southern Yunnan Province, China.

BACKGROUND: Culicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses. At least 20 species are considered as vectors or potential vectors of bluetongue virus (BTV) which cause bluetongue disease in ruminants. A BTV prevalence of 30-50% among cattle and goats in tropical southern Yunnan Province, China, prompted an investigation of the potential BTV vectors in this area. METHODS: Culicoides were collected by light trapping at three sites in the tropical region of Yunnan Province. Species were identified based on morphology and DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in these specimens. Phylogenetic analysis was used to analyze the cox1 sequences of Culicoides specimens infected with BTV. RESULTS: Approximately 67,000 specimens of Culicoides were collected, of which 748 were tested for the presence of BTV. Five specimens, including two of Culicoides jacobsoni, one of C. tainanus and two of C. imicola, were identified as infected with BTV. No specimens of C. (subgenus Trithecoides) or C. oxystoma tested were positive for BTV infection. CONCLUSIONS: To our knowledge this is the first report of C. jacobsoni as a potential BTV vector and the fourth report of an association between C. tainanus and BTV, as well as the first direct evidence of an association between BTV and C. imicola in Asia. A fourth potential cryptic species within C. tainanus was identified in this study. Further analysis is required to confirm the importance of C. jacobsoni and C. tainanus in BTV epidemiology in Asia.

Comparison of immunogenicity between hepatitis B vaccines with different dosages and schedules among healthy young adults in China: A 2-year follow-up study.

Immunogenicity of hepatitis B vaccine between 20 µg with 3-dose schedule and 60 µg with 2-dose regimens was compared 2 years after primary immunization. A total of 353 healthy adults aged 18-25 years were enrolled in the study and randomly assigned (1: 1: 1) into 3 vaccine groups: A (20 µg, 0-1-6 month), B (60 µg, 0-1 month) and C (60 µg, 0-2 month). Serum samples were collected at 1 month after a series vaccination and 12 months, 24 months after the first-dose. The GMC level of anti-HBs antibody was measured using Chemiluminescent Microparticle ImmunoAssay (CMIA). There were 59, 45 and 55 vaccinees available to follow-up with 2 year later in vaccine groups A, B and C, respectively. No significant differences existed in sex ratio, age and body mass index (BMI) among vaccinees at month 24 and the corresponding participants at baseline in each group (P > 0.05). The seroprotection rates in group A, B and C were 98.31%, 88.37% and 85.19%, respectively (P = 0.014), reflecting the fact that the rate of group A was significantly higher than that in group C (P = 0.026). Also, the GMC level of anti-HBs antibody in group A was significantly higher than those of other two groups (427.46 mIU/ml vs. 89.74 mIU/ml, 89.80 mIU/ml, respectively; all P < 0.01). This data suggested that the standard 20 µg (0-1-6 month) regimen of hepatitis B vaccine should be recommended as a priority on the premise of complete compliance in adults.

Comparative immunogenicity of hepatitis B vaccine with different dosages and schedules in healthy young adults in China.

OBJECTIVES: To compare immunogenicity of hepatitis B vaccine between the standard 3-dose (20 µg) and 2-dose with higher-dosage (60 µg) regimens in healthy young adults and evaluate the safety profile. METHODS: A randomized, parallel-group clinical trial was conducted among healthy young adults aged 18-25 years. Subjects were randomly assigned to three groups. One group was administered hepatitis B vaccine with the standard regimen of 0-1-6 month (20 µg) and other groups were immunized with regimens of 0-1 or 0-2 month (60 µg) respectively. Serum samples were collected at 1 month after a series vaccination and 12 months after the first-dose inoculation for anti-HBs antibody measurement with a Chemiluminescent Microparticle ImmunoAssay (CMIA). RESULTS: The seroprotection rates in 20 µg (0-1-6 month), 60 µg (0-1 month) and 60 µg (0-2 month) groups were 100, 93.64 and 99.19% at month 7/2/3, and 100, 96.04 and 95.90% at month 12, respectively. There were no significant differences among three vaccine groups (p>0.05). The geometric mean concentration (GMC) of anti-HBs was significantly higher in 20 µg (0-1-6 month) group than that in 60 µg (0-1 month) group at month 7/2 (1847.99 vs. 839.27 mIU/ml, p=0.004), but was similar to that in 60µg (0-2 month) group at month 7/3 (1847.99 vs. 1244.80 mIU/ml, p=0.138). At month 12, the GMC in 20 µg (0-1-6 month) group was significantly higher than those of other groups (1456.63 vs. 256.30, 235.15 mIU/ml, respectively, p<0.001). The total incidence of injection-site or systemic adverse reactions was <3%. CONCLUSIONS: A 2-dose with higher-dosage hepatitis B vaccine regimens are comparable to the standard 3-dose regimen in terms of immunogenicity except a relatively rapid decline in GMC levels which are associated with the longevity of protection. All formulations of hepatitis B vaccine were well tolerated. CLINICALTRIALS.GOV IDENTIfiER: NCT02203357.

Biotransformation of 1,3-propanediol cyclic sulfate and its derivatives to diols by Rhodococcus sp.

Rhodococcus sp. CGMCC 4911 transformed 1,3-propanediol cyclic sulfate (1,3-PDS) and its derivatives into corresponding diols. Ethylene sulfate, glycol sulfide, 1,3-PDS, and 1,2-propanediol cyclic sulfate were effectively hydrolyzed with growing cells. (R)-1,2-Propanediol (>99 % e.e.) was obtained at 44 % yield with growing cells. Glycol sulfide, ethylene sulfate, and 1,3-PDS were converted into the corresponding diols at 94.6, 96.3, and 98.3 %, respectively. Optimal reaction conditions with lyophilized resting cells were 30 °C, pH 7.5, and cell dosage 17.9 mg cell dry wt/ml. 1,3-Propanediol was obtained from 50 mM 1,3-PDS at 97.2 % yield by lyophilized cells after 16 h. Lyophilized cells were entrapped in calcium alginate with a half-life of 263 h at 30 °C, and the total operational time of the immobilized biocatalysts could reach over 192 h with a high conversion rate.

Discovery of a reductase-producing strain recombinant E. coli CCZU-A13 using colorimetric screening and its whole cell-catalyzed biosynthesis of ethyl (R)-4-chloro-3-hydroxybutanoate.

An NADH-dependent reductase (SsCR) was discovered by genome data mining. After SsCR was overexpressed in E. coli BL21, recombinant E. coli CCZU-A13 with high reductase activity and excellent stereoselectivity for the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (R)-4-chloro-3-hydroxybutanoate ((R)-CHBE) was screened using one high-throughput colorimetric screening strategy. After the reaction optimization, a highly stereoselective bioreduction of COBE into (R)-CHBE (>99% ee) with the resting cells of E. coli CCZU-A13 was successfully demonstrated in n-butyl acetate-water (10:90, v/v) biphasic system. Biotransformation of 600mM COBE for 8h in the biphasic system, (R)-CHBE (>99% ee) could be obtained in the high yield of 100%. Moreover, the broad substrate specificity in the reduction of aliphatic and aromatic carbonyl compounds was also found. Significantly, E. coli CCZU-A13 shows high potential in the industrial production of (R)-CHBE (>99% ee) and its derivatives.

Biosynthesis of ethyl (S)-4-chloro-3-hydroxybutanoate by NADH-dependent reductase from E. coli CCZU-Y10 discovered by genome data mining using mannitol as cosubstrate.

The reductase (PgCR) from recombinant Escherichia coli CCZU-Y10 displayed high reductase activity and excellent stereoselectivity for the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (S)-4-chloro-3-hydroxybutanoate ((S)-CHBE). To efficiently synthesize (S)-CHBE (>99 % enantiomeric excess (ee)), the highly stereoselective bioreduction of COBE into (S)-CHBE with the whole cells of E. coli CCZU-Y10 was successfully demonstrated in a dibutyl phthalate-water biphasic system. The appropriate ratio of the organic phase to water phase was 1:1 (v/v). The optimum reaction temperature, reaction pH, cosubstrate, NAD(+), and cell dosage of the biotransformation of 100 mM COBE in this biphasic system were 30 °C, 7.0, mannitol (2.5 mmol/mmol COBE), 0.1 µmol/(mmol COBE), and 0.1 g (wet weight)/mL, respectively. Moreover, COBE at a high concentration of (1,000 mM) could be asymmetrically reduced to (S)-CHBE in a high yield (99.0 %) and high enantiometric excess value (>99 % ee). Significantly, E. coli CCZU-Y10 shows high potential in the industrial production of (S)-CHBE (>99 % ee).

Highly efficient synthesis of ethyl (S)-4-chloro-3-hydroxybutanoate and its derivatives by a robust NADH-dependent reductase from E. coli CCZU-K14.

An NADH-dependent reductase (CmCR) from Candida magnoliae was discovered by genome mining for carbonyl reductases. After CmCR was overexpressed in Escherichia coli BL21, a robust reductase-producing strain, recombinant E. coli CCZU-K14, was employed for the efficient synthesis of ethyl (S)-4-chloro-3-hydroxybutanoate ((S)-CHBE) from the reduction of ethyl 4-chloro-3-oxobutanoate (COBE). After the optimization, the optimum reaction conditions were obtained. Notably, E. coli CCZU-K14 had broad substrate specificity in reducing both aliphatic and aromatic substrates, and excellent enantioselectivity of CCZU-K14 was observed for most of the tested substrates, resulting in chiral alcohols of over 99.9% ee. Moreover, COBE at a high concentration of (3000mM) could be asymmetrically reduced to (S)-CHBE in the high yield (>99.0%) and high enantiometric excess value (>99.9% ee) after 14h. Significantly, E. coli CCZU-K14 shows high potential in the industrial production of (S)-CHBE and its derivatives (>99.9% ee).

Highly enantioselective oxidation of phenyl methyl sulfide and its derivatives into optically pure (S)-sulfoxides with Rhodococcus sp. CCZU10-1 in an n-octane-water biphasic system.

Enantiopure sulfoxides can be prepared via the asymmetric oxidation of sulfides using sulfide monooxygenases. The n-octane-water biphasic system was chosen for the bio-oxidation of a water-insoluble phenyl methyl sulfide (PMS) by Rhodococcus sp. CCZU10-1. In this n-octane-water system, the optimum reaction conditions were obtained. (S)-phenyl methyl sulfoxide ((S)-PMSO) with >99.9 % enantiomeric excess formed at 55.3 mM in the n-octane-water biphasic system. Using fed-batch method, a total of 118 mM (S)-PMSO accumulated in 1-L reaction mixture after the 7th feed, and no (R)-PMSO and sulfone were detected. Moreover, Rhodococcus sp. CCZU10-1 displayed fairly good activity and enantioselectivity toward other sulfides. In conclusion, Rhodococcus sp. CCZU10-1 is a promising biocatalyst for synthesizing highly optically active sulfoxides.