•The effect of hydrothermal, NaOH, and EDA pretreatment on CKK was compared.•EDA showed a better de-crystallization effect on CKK compared to other pretreatment.•Addition nutrient in enzymatic ...hydrolysate helps bacterial cellulose (BC) production.•4.6 g/L BC was produced in EDA-pretreated CKK enzymatic hydrolysate.
In this study, three different pretreatment technologies (hydrothermal, NaOH, and ethylenediamine (EDA) pretreatment) were investigated to improve the efficiency of the enzymatic conversion of Caragana korshinskii Kom. (CKK). The effects of the pretreatment conditions on the composition, structure, and enzymatic hydrolysis of CKK were evaluated. The results indicated that EDA pretreatment was more effective in promoting CKK digestibility than the other pretreatments. EDA exhibited a good delignification ability (up to 72.8%) and a strong de-crystallization effect (up to 29.9%) compared to hydrothermal and NaOH pretreatment. The best result for the cellulose enzymatic conversion (88.0%) was obtained at 210 °C for 40 min with 30 mL EDA. Using of the EDA-pretreated CKK as a substrate for bacterial cellulose (BC) production indicated that a lower nutrient level in the enzymatic hydrolysate medium could be a key factor that impedes the fermentation performance of Gluconacetobacter xylinus. The addition of extra nutrients promoted BC production efficiency, and under optimized conditions, the BC yield was 4.6 g/L.
Parthenolide, a kind of sesquiterpene lactone, is the direct precursor for the promising anti-glioblastoma drug ACT001. Compared with traditional parthenolide source from plant extraction, de novo ...biosynthesis of parthenolide in microorganisms has the potential to make a sustainable supply. Herein, an integrated strategy was designed with P450 source screening, nicotinamide adenine dinucleotide phosphate (NADPH) supply, and endoplasmic reticulum (ER) size rewiring to manipulate three P450s regarded as the bottleneck for parthenolide production. Germacrene A oxidase from Cichorium intybus, costunolide synthase from Lactuca sativa, and parthenolide synthase from Tanacetum parthenium have the best efficiency, resulting in a parthenolide titer of 2.19 mg/L, which was first achieved in yeast. The parthenolide titer was further increased by 300% with NADPH supplementation and ER expanding stepwise. Finally, the highest titers of 31.0 mg/L parthenolide and 648.5 mg/L costunolide in microbes were achieved in 2.0 L fed-batch fermentation. This study not only provides an alternative microbial platform for producing sesquiterpene lactones in a sustainable way but also highlights a general strategy for manipulating multiple plant-derived P450s in microbes.
Here, we report the successful design, construction, and characterization of a 770-kilobase synthetic yeast chromosome II (synII). Our study incorporates characterization at multiple levels-including ...phenomics, transcriptomics, proteomics, chromosome segregation, and replication analysis-to provide a thorough and comprehensive analysis of a synthetic chromosome. Our Trans-Omics analyses reveal a modest but potentially relevant pervasive up-regulation of translational machinery observed in synII, mainly caused by the deletion of 13 transfer RNAs. By both complementation assays and SCRaMbLE (synthetic chromosome rearrangement and modification by
-mediated evolution), we targeted and debugged the origin of a growth defect at 37°C in glycerol medium, which is related to misregulation of the high-osmolarity glycerol response. Despite the subtle differences, the synII strain shows highly consistent biological processes comparable to the native strain.
The synthetic chromosome rearrangement and modification by loxP-mediated evolution (SCRaMbLE) system has been used to improve prodeoxyviolacein (PDV) production in haploid yeast containing chromosome ...synV. To rapidly and continuously generate genome diversification with the desired phenotype, the multiplex SCRaMbLE iterative cycle strategy has been developed for the screening of high PDV production strains. Wholegenome sequencing analysis reveals large duplications, deletions, and even the whole genome duplications. The deletion of
YER151C
is proved to be responsible for the increase. This study demonstrates that artificial DNA rearrangement can be used to accelerate microbial evolution and the production of biobased chemicals.
Chinese wolfberry is a widely used traditional medicine‐food homology plant with diverse functions. However, as Chinese wolfberry contains abundant monosaccharides, it cannot be consumed by diabetic ...and obese people, which reduces its health and commercial value. To remove monosaccharide, raw Chinese wolfberry juice was fermented by Komagataeibacter xylinus. Glucose was exhausted after 10 days, and maximum 3.145 g/L bacterial cellulose was obtained. The total organic acid and amino acid concentration increased from 2,974.32 mg/100 ml and 409.19 mg/100 ml to 4,217.7 mg/100 ml and 655.1 mg/100 ml, respectively. Fermentation promoted the generation of esters, volatile acids, aldehydes, and ketones, but no observed change in polysaccharide concentration was detected. Fermentation enhanced the contents of flavonoid and polyphenol, and antioxidant ability was also increased.
Novelty impact statement
This is the first study that removed monosaccharide from Chinese wolfberry juice by Komagataeibacter xylinus fermentation.
K. xylinus not only removed the glucose after fermentation, but it also generated bacterial cellulose (BC). As a food‐grade functional biofilm, BC is worthy of further study.
The concentration of glucose was reduced effectively; however, active ingredients were not affected by fermentation.
Herein we report the successful design, construction and characterization of a 770 kb synthetic yeast chromosome
II
(
synII
). Our study incorporates characterization at multiple levels, including ...phenomics, transcriptomics, proteomics, chromosome segregation and replication analysis to provide a thorough and comprehensive analysis of a synthetic chromosome. Our “Trans-Omics” analyses reveal a modest but potentially significant pervasive up-regulation of translational machinery observed in
synII
is mainly caused by the deletion of 13 tRNAs. By both complementation assays and SCRaMbLE, we targeted and debuged the origin of a growth defect at 37°C in glycerol medium, which is related to misregulation of the HOG response. Despite the subtle differences, the
synII
strain shows highly consistent biological processes comparable to the native strain.
As a typical class of environmental endocrine disruptors, bisphenol A poses a potential threat to the sustainable survival and reproduction of living beings and human beings. In this study, the ...interaction between Trametes versicolor laccase and bisphenol A (BPA) was studied by molecular docking simulation, and the catalytic degradation of BPA was verified by experiments. The conditions for the laccase production of T. versicolor were optimized by orthogonal design, and the degradation of BPA was studied using its crude enzyme solution. The optimum degradation conditions were obtained by response surface methodology (RSM). Ultimately, the transformation products after 3 and 6 h of reaction were detected by gas chromatography–mass spectrometry. Docking results demonstrated that the reaction between laccase and BPA was spontaneous, and the degradation rate in 24 h reached 88.76%. RSM results showed that the highest BPA degradation rate of 97.68% was reached after 1 h reaction at 44.6 °C, 5 mg/L initial BPA concentration, and pH 5.20. The intermediate products of BPA catalyzed by laccase included ethylbenzene, p-xylene, and cyclohexanone 1-methyl-4-isopropenyl-2-cyclohexenol. This finding reveals that BPA degradation by the crude laccase from T. versicolor starts from the C atoms between two benzene rings that connect BPA. Compared with expensive pure enzyme, the crude laccase solution prepared by T. versicolor showed greater efficiency in BPA degradation. This work provides theoretical references and experimental methods for the biological processing of harmful pollutants.
•The interaction between laccase and BPA was simulated by molecular docking.•The optimum conditions for laccase production were obtained by orthogonal design.•The optimum conditions for the degradation of BPA were obtained by RSM.•The transformation products of BPA were detected by GC–MS.•The intermediate reaction of transformation was deduced.
Background:Atrial fibrillation (AF) recurrence remains a tricky problem in patients undergoing ablation. This meta-analysis aimed to summarize the current literature to clarify whether ...renin-angiotensin system inhibitors (RASIs) prevent AF recurrence after ablation.Methods and Results:Relevant studies were searched on Pubmed and EMBASE through December 2019. Pooled relative risk (RR) of AF recurrence was calculated. Subgroup analyses according to study design, race, and follow-up duration were further performed. A total of 15 studies examining 4,300 patients were included, with 3 randomized controlled trials and 12 cohort studies. Overall analysis showed that RASIs significantly reduced AF recurrence after ablation (RR=0.83; 95% confidence interval (CI) 0.70–0.98, P=0.028; I2=68.9%). Subgroup analysis further indicated that positive results were found in randomized controlled trials (RR=0.51, 95% CI 0.37–0.70, P<0.001; I2=4%), studies conducted in Asia (RR=0.59, 95% CI 0.46–0.76, P<0.001; I2=30.7%), and studies with follow-up duration ≥1 year (RR=0.82, 95% CI 0.70–0.95, P=0.01; I2=59.1%); negative results were found in cohort studies, studies conducted in Europe or the USA, and studies with follow-up duration <1 year.Conclusions:RASIs can potentially prevent AF recurrence after ablation under selected conditions. However, more studies are required to confirm this finding due to the variation in current evidence.
An unmanned aerial vehicle (UAV)-enabled intelligent transportation system utilizes a set of UAVs to collect and process surveillance data for transportation management. Subsequently, the processing ...results of the UAVs are transmitted to a control center that makes a centralized transportation management decision based on the fusion of all processing results. When performing the monitoring tasks, the UAVs can access to an edge server for offloading. To reduce the energy consumption and improve the fusion performance, the control center schedules the UAVs to perform the tasks in an energy-efficient manner while synchronizing the completion time of the UAVs. As a result, the control center studies a constrained multi-objective optimization problem (CMOP), in which two objectives, i.e., the total energy consumption of the UAVs and total completion time difference among the UAVs, are simultaneously considered. To tackle the CMOP, we develop an improved constrained multi-objective evolutionary algorithm. Particularly, we design an improved genetic operator and repairing constraint-handling technique to improve the overall performance of the proposed algorithm in seeking Pareto optimal solutions for the CMOP. Numerical results demonstrate that compared with the baseline algorithms, the proposed algorithm has great advantages in finding better solutions with the enhanced diversity and convergence for the CMOP.
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