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Abstract:[Objective] The succession of community structure and potential functional composition of Clostridia in fermented grains of Luzhou-flavor liquor during the fermentation process were studied. [Methods] Real-time quantitative PCR combined with high-throughput sequencing was used to study the dynamics of Clostridia community in fermented grains. 16S rRNA genehigh-throughput sequencing using specific primers was conducted to reveal the succession of Clostridia community. Biomarkers were located on OTU-level through LEfSe analysis. Predictive functional composition of Clostridia community was studied using PICRUSt. [Results] The biomass and relative abundance of Clostridia community reached their maxima at 14 d (3.46×107 copies/g) and 20 d (6.67%), respectively. Clustering analysis showed that the structure of Clostridiacommunity in 7-dsample was significantly different from that in other samples. 17 OTUs were located as biomarkers, and the BLAST results of these OTUs indicated that most of them represented unclassified bacteria. PICRUSt analysis showed that Clostridia community mainly participated in amino sugar and nucleotide sugar metabolism and pentose phosphate pathway followed by fructose and mannose metabolism, citrate cycle, glycolysis, propanoate and butanoate metabolism. [Conclusion] The biomass and the relative abundance of Clostridia community in fermented grains of Luzhou-flavor liquor reached their maxima after being fermented for two to three weeks. The structure of Clostridia community shifted significantly during the first week of fermentation and then gradually recovered in the following two weeks. A number of predictive functional genes related to the metabolism of flavor compounds such as propanoate and butanoate were detected in Clostridia community during 14?21 d of fermentation.

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Abstract:[Objective] To increase the activity of the whole-cells, reduce the fermentation period and improve production efficiency, high molecular mass nitrile hydratase (H-NHase) from Rhodococcus rhodochrous J1 was over-expressed in Escherichia coli. [Methods] The native SD sequence upstream of the α-subunit gene nhhA and the activator gene nhhG was substituted by a stronger SD sequence, and the length of the intergenic region between the two genes was optimized. In addition, the rare codons within the gene were optimized. The modified nhhBAG was over-produced in recombinant E. coli BL21(DE3). After purification by ion-exchange chromatography, the molecular mass for the recombinant enzyme was determined by Size-exclusion chromatography. The catalytic conditions were optimized, and the process of biosynthesis of nicotinamide was simulated with continuous substrate-flow. [Results] H-NHase was successfully over-expressed in E. coli. The activity in cell-free extracts and the specific activity of the purified enzyme were 85.5±4.3 U/mg and 234.0±11.7 U/mg by using 3-Cyanopyridine as substrate, respectively. The molecular mass for recombinant H-NHase was 504.5±9.8 kD. The optimal catalysis pH, temperature, and substrate concentration using whole cells were 7.5, 25 °C, 400 mmol/L, respectively. The whole-cell activity was up to 256.0±10.4 U/mL. Under this condition, the transformation ratio by whole-cell was 99.9%. [Conclusion] The recombinant E. coli grows fast with a shorter fermentation period. The production efficiency of amides using the recombinant strain would be increased, which exhibits potential value for industrial production.

Abstract:[Objective] In order to increase the activity of a cold-adapted superoxide dismutase (SOD) from Lactobacillus plantarum sp. CLP0279. [Methods] Based on the single-factor experiment, the fermentation medium for the production of SOD was optimized using Plackett-Burman method, Box-Behnken design and response surface analysis. [Results] The optimal fermentation medium (g/L) was determined as follows: corn meal powder 25.000, KH2PO4 2.600, K2HPO4 1.830, CuSO4·5H2O 0.011, ZnSO4·7H2O 0.014. Under these conditions, the maximum activity of SOD was 194.82 U/mL, which was 1.36 times comparing to that before optimization. [Conclusion] The activity of the cold-adapted SOD was obviously increased after optimization and three crucial factors (K2HPO4, CuSO4·5H2O and ZnSO4·7H2O) were verified by the response surface analysis, which might provide a foundation for the scale-up culture in the future.

Abstract:[Objective] In order to explore actinobacteria resources, the diversity, antimicrobial activity and secondary metabolites biosynthesis genes of endophytic actinobacteria isolated from Glycyrrhizain flata Bat. were studied. [Methods] 80 endophytic actinobacteria strains were isolated from Glycyrrhizain flata Bat. by employing five selective media and three isolated procedures. 36 representative strains were selected for antimicrobial activity analysis and amplifying genes coding for polyketide synthases (PKS I, PKS II), nonribosomal peptide synthetases (NRPS) and halogenated enzyme gene (Halo). Based on the results of antimicrobial activity, 20 representatives were chosen for 16S rRNA gene sequencing. [Results] The better separating conditions were observed with Medium E2 and E3 combined with dry-air treatment. 86.1% out of 36 representative strains showed antimicrobial activity against at least one of tested pathogenic organisms, and the number of strains with PKSI, PKSII, NRPS and halogenated enzyme gene fragments matching the anticipated length were 16.7%, 72.2%, 25.0%, 11.1%. According to the phylogenetic analysis, twenty isolates were belonging to Streptomyces, Micromonospora, Rhodococcus and Actinoplanes, respectively. Streptomyces was the most common endophytic actinobacteria of Glycyrrhizain flata Bat., accounting for above 60%. [Conclusion] Liquorice is traditional chinese medicinal plant, the strains isolated from Glycyrrhizain flata Bat. are potent source which produce multiple compounds and can be further explored.

Abstract:[Objective] In order to study the community diversity of shiroes soil, shiroes of Leccinum extremiorientale (Le), Boletus edulis (Be) and Tylopilus microsporus (Tm) were investigated. [Methods] Bacterial diversity and community structure of shiroes of these wild Boletus were analyzed via high throughput sequencing. [Results] Major phyla of Le, Be and Tm were Proteobacteria (53.6%), Acidobacteria (33.8%), Bacteroidetes (4.7%), Actinobacteria (1.7%); Acidobacteria (40.7%), Proteobacteria (38.1%), Bacteroidetes (10.3%); Acidobacteria (65.3%), Proteobacteria (23.8%) and Bacteroidetes (4.9%), respectively. The dominant genera of Le, Be and Tm were unclassified bacteria (69.8%), Burkholderia (16.0%), Candidatus Solibacter (5.9%), Acidocella (3.3%); unclassified bacteria (83.0%), Candidatus Solibacter (8.0%), Burkholderia (2.1%); unclassified bacteria (80.9%), Candidatus Solibacter (12.6%), respectively. [Conclusion] The bacterial diversity is abundant in the three shiroes and there are a number of unclassified bacteria.

Abstract:[Objective] The aim of this study is to isolate the arbuscular mycorrhizal fungi (AMF) from different ecological environments in China, and lay the foundation for the research of AMF. [Methods] Relying on sorghum as the host plant, AMF strains were isolated from the soil using the trap cultures, single species cultures and stimulation of sporulation technologies respectively, followed by the species identification. [Results] One hundred and thirty-five AMF strains belonging to 23 species were isolated from the rhizosphere soil of over 50 host plants in 45 regions of China, and their morphological characteristics were described. [Conclusion] China is rich in the arbuscular mycorrhizal fungi resource, and the species resource.

Abstract:[Objective] This study aimed to monitor noroviruses (NoVs) in the water environment and human population in Shenzhen city, and to explore the relationship for NoVs circulation between the two media. [Methods] Twenty-four water samples from Maozhou River and 287 clinical specimens were collected in Shenzhen city from March 2014 to February 2015. Water samples were firstly concentrated by mixed cellulose ester microporous membrane and PEG, and clinical specimens were directly diluted for RNA extraction. NoVs were firstly detected through real time RT-PCR, and the ORF2 capsid protein gene (VP1) of NoVs were got by RT-PCR and sequenced for genotype analysis. Homology and phylogenetic analyses were performed to investigate the relationship between the NoVs from environment water and those from human population. [Results] The positive rate for the water samples was 23.1%, including 8.3% and 41.7% positive rates for the upstream and downstream samples, respectively; while the positive rate for clinical specimens was 17.4%. The positive rate of genotype NoVGI and GII was 16.7% and 8.3% in the water samples, respectively. The VP1 partial gene sequence analysis showed that GI.6 was predominant in the water samples, in which GII.4 Sydney_2012 was also detected. Meanwhile, compared with GGII.3, GII.4 Sydney_2012 was more prevalent in human population. The nucleotide homology of partial VP1 gene of GII.4 Sydney_2012 from different samples showed 98.2%–100.0%. [Conclusion] NoVGII.4 Sydney_2012 was the predominant genotype in human population of Shenzhen city. To some extent, NoVs were probably circulating between water environment and human population.

Abstract:[Objective] This study focus on the functional characterization of membrane-bound cytochrome b5 reductase I from Mortierella alpina ATCC 32222. [Methods] We identified the N-terminal transmembrane region in the M. alpina cytochrome b5 reductase I through sequence alignment. The truncated M. alpina cytochrome b5 reductase I gene and human soluble cytochrome b5 gene were expressed in Escherichia coli BL21. The proteins were purified using Cobalt affinity, ion exchange and gel filtration. The activity of purified cytochrome b5 reductase I was determined using DCIP as substrate in the presence of NADH or NADPH. The interaction between purified cytochrome b5 reductase I and cytochrome b5 was monitored by wavelength scan. [Results] The truncated M. alpina cytochrome b5 reductase I was successfully expressed as a soluble protein and purified to homogeneity. The resulting protein was active and able to reduce cytochrome b5 in the presence of NADH. The reduction of cytochrome b5 is characterized by a peak shift from 411 nm to 422 nm and an increase in absorbance at 521 nm and 554 nm. [Conclusion] The deletion of the N-terminal transmembrane region increased the solubility of M. alpina cytochrome b5 reductase I and the activity was maintained. Functional characterization revealed that M. alpina cytochrome b5 reductase I gene encoded a NADH-cytochrome b5 reductase, and it’s able to interact with human cytochrome b5 in vitro.

Abstract:[Objective] A novel chitinase gene was cloned from the genomic DNA of psychrophilic bacterium, Pseudoalteromonas sp. DL-6 and heterologously expressed in Escherichia coli BL21(DE3). The recombinant protein was purified and the enzymatic hydrolysates were analyzed. [Methods] The chitinase gene, chiA, was amplified from Pseudoalteromonas sp. DL-6 by using a PCR protocol, linked to pET28a, and finally expressed in E. coli BL21(DE3). The molecular weight and purity were determined by SDS-PAGE, and enzymatic activity was detected by 4-methylumbelliferyl-β-D-N,N′-diacetylchitobioside (4MU-(GlcNAc)2). The hydrolysis products were identified by electrospray ionisation mass spectrometry (ESI-MS). [Results] The chiA (GenBank: KF234015) was efficiently expressed in E. coli BL21(DE3), and the total activity of purified ChiA was 168.68 U using Ni-NTA resin. ESI-MS analysis showed that the hydrolysis products of 1% colloidal chitin after ChiA digestion consisted of a series of chitin oligomers. [Conclusion] The research provided a reference for endo-type ChiA used in the food, pharmaceutical and agricultural industry.

Abstract:[Objective] Among collected plant growth-promoting rhizobacteria (PGPR), we explored the plant growth-promoting mechanism of Bacillus subtilis JC01 producing volatile organic compound. [Methods] Among 838 bacterial strains isolated from rhizosphere soil, 107 strains were selected for amplified ribosomal DNA restriction analysis, according to their activities of nitrogen fixation, organic phosphorus decomposition, inorganic phosphorus solubilization, and indole-3-acetic acid (IAA) and siderophore production in vitro. A total of 20 potential bacteria from different clusters were assessed for the relationship between the assessment system and their plant growth promotion in greenhouse. The expression level of plant hormone signaling pathways related genes in tomato exposed to volatile organic compound (VOC) produced by JC01 was tested by real-time PCR. [Results] Four strains had high plant growth-promoting efficiency on different crops. Moreover, JC01 could produce VOC that efficiently promoted plant growth, and the emission upregulated the expression of IAA signaling pathway related gene, and downregulated that of abscisic acid (ABA) and ethylene (ETH) signaling pathways related genes. The 16S rRNA gene sequencing data defined that JC01 was Bacillus subtilis. [Conclusion] Bacillus subtilis JC01 promoted plant growth by producing VOC.

Abstract:[Objective] To explore potent antagonistic microorganisms in bee bread, an antagonistic strain PC2 isolated from bee bread was identified, and its antimicrobial characteristics were evaluated. [Methods] Antagonistic spectrum and effect of thermal, pH, UV irradiation and protease on fermentation broth inhibitory activity were assessed by Oxford cup plate assay; strain identification was based on morphology, physiological and biochemical characteristics and 16S rRNA gene sequence analysis. The antimicrobial protein and lipopeptide compounds were separated by ammonium sulfate precipitation and acid-precipitate organic solvent extraction method, respectively. [Results] A total of 17 antagonistic microorganisms were isolated from 3 different bee bread samples. Strain PC2 fermentation broth cultured in Potato Dextrose Broth showed excellent antimicrobial activity against 7 tested microorganisms. Strain PC2 was preliminary identified as Bacillus amyloliquefaciens by morphological, physiological and biochemical characteristics combined with 16S rRNA gene sequence analysis. The antimicrobial activity of fermentation broth was not sensitive to temperature, acidity and UV irradiation. However, fermentation broth treated with pepsin, alkaline proteinase and protease K lost antimicrobial activity. Proteins and lipopeptides were the main antimicrobial compounds. [Conclusion] Strain PC2 isolated from bee bread has potent applications in food preservation and agricultural biological control.

Abstract:[Objective] In order to isolate and screen a high-affinity siderophore-producing bacteria from calcareous soil, which has a significant effect on the pathogen. [Methods] High-affinity siderophore-producing strains were screened by chrome azural S (CAS) assay. Then, we take the methods of morphological observation, biochemical and physiological characteristics, 16S rRNA gene sequence and phylogenetic analysis to identify the bacterial species. Based on the results obtained from strain’s screening and identification, antagonism between strains and pathogenic bacteria was researched by dual culture on potato dextrose agar. [Results] Siderophore-producing bacteria HMGY6B identified as Pseudomonas was isolated and screened out from the ryegrass (Lolium perenne L.) rhizosphere soil, which produced Catechol-type siderophore had the significant effects on cucumber gray mold (Botrytis cinerea). The inhibition ratio was up to 91.2% under low iron conditions (0.16, 2, 5, 10 μmol/L FeCl3). But unfortunately, it decreased to 30.2% under 50 μmol/L FeCl3 and only 5.5% under Fe-replete conditions (100 μmol/L FeCl3). [Conclusion] The srtain HMGY6B can be used to the exploitation and development of compound disease-resistant manure.

Abstract:[Objective] Shallot Fusarium rot disease occurred constantly during storage. It was important for controlling the disease to confirm the pathogenic Fusarium species of the disease. [Methods] The pathogens of shallot storage Fusarium rot disease were isolated and cultured purely by tissue isolation method from 16 samples collected from Lanzhou markets in Gansu province, China. The generated Fusarium strains were identified by morphological characteristics and analysis of rDNA-ITS, EF-1a(tef) gene sequences after single spore isolation. [Results] The generated 80 Fusarium strains belonged to three species including F. proliferatum, F. oxysporum and F. avenaceum. F. proliferatum with 52.50 percentage isolation frequencies was the dominant pathogen of shallot Fusarium rot disease. The pathogenicity test showed that the pathogenicity of F. proliferatum was the strongest in shallot bulbs among the three Fusarium species, F. avenaceum was the weakest. [Conclusion] Three pathogenic Fusarium species were firstly reported as the pathogens of shallot storage Fusarium rot disease in Ganshu province, China.

Abstract:[Objective] To analyze lysine biosynthetic pathway and related genes based on the whole genome of Flammulina velutipes. [Methods] Genome sequence of the monosporous strain Dan3 was sequenced through Illumina Hiseq2000 and Roche454 FLX+. Key genes related to lysine biosynthesis pathway were screened based on the whole genome. Basic physical and chemical properties of these proteins were analyzed, and the subcellular localization and secondary structure were predicted. [Results] The sequenced reads were assembled and 34.17 Mb length genome sequence of Dan3 was obtained. The structure of 8 key genes involved in α-aminoadipate pathway was identified. Each gene was composed of a number of introns and exons, and the secondary structure was mainly composed of α-helix and irregular curl. Three of these proteins were localized to the mitochondria. [Conclusion] The de novo biosynthesis of lysine in F. velutipes was through the α-aminoadipate pathway, and almost all enzymes involved in this pathway were predicted in the whole genome of F. velutipes.

Abstract:[Objective] To study the association of biofilm formation ability with drug-resistance and virulence of Escherichia coli isolated from diarrhea piglets. [Methods] In total 129 strains of clinically isolated and identified pathogenic E. coli were collected. The in vitro biofilm formation, the drug-resistance phenotype, the minimal inhibitory concentration (MIC) of biofilm bacteria and planktonic, and the median lethal dose (LD50) in mice were then evaluated by the 96-well micro plate method, the K-B method, the micro dilution method, and the Curtiss modified method, respectively. [Results] The positive rate of biofilm formation was 96.1% among the 129 isolates with the majority of them to be lowly positive. The resistance rate to tetracycline, ampicillin and amoxicillin was 92.2%, 92.2%, and 93%, respectively. The lowest resistance rate to imipenem was 1.6%. Ninety-four multi resistant phenotypes were displayed in the isolates, with 86% of them to be amoxicillin-ampicillin-tetracycline-doxycycline-cotrimoxazole-trimethoprim, which was the most frequent type and was correlated to ciprofloxacin, florfenicol, levofloxacin, norfloxacin, cephradine and cefoperazone (p<0.05). The MIC of ciprofloxacin and florfenicol on biofilm bacteria was 2–16 and 8?16 times, respectively, higher than on planktonic bacteria. Isolates with biofilm formation 3+ showed the highest LD50. [Conclusion] Pathogenic E. coli in diarrhea piglets showed the biofilm formation ability and were multi-resistant. Drug resistance of bacteria with biofilm formation to ciprofloxacin and florfenicol was positively correlated to the biofilm formation ability, and LD50 also increased with a stronger biofilm formation ability.

Abstract:[Objective] We aim to get a high-yield poly-β-hydroxybutyricacid (PHB) mutant strain. [Methods] We use composite multiple rounds of mutagenesis breeding of UV and diethyl sulfate and after primary and secondary screening from the original strain Pseudomonas koreensis PK3. [Results] It’s named Pseudomonas koreensis UVCN-18. After serially passed 9 times and fermentation 28 h, PHB production of the mutant was 15.94 g/L, Accounting for cell dry weight 69.54%. PHB production of the mutant was increased by 2.61 times compared with the original strain Pseudomonas koreensis PK3 (4.42 g/L), and the strain has a good genetic stability. [Conclusion] We use composite multiple rounds of mutagenesis breeding of UV and diethyl sulfate to get a high-yield PHB mutant strain.

Abstract:[Objective] A total of 26 Edwardsiella tarda isolates were characterized by automated ribotyping and cluster analysis. [Methods] Strains of E. tarda taken from Channel Catfish, Japanese eel, Turbot, flounder, sweet spot were analyzed by the DuPont RiboprinterTM Microbial Characterization System and we adopted a protocol using EcoRⅠ as restriction enzyme to differentiate and characterize the isolates discussed here. The Riboprinter patterns obtained for the 26 isolates were imported and analyzed with BioNumerics software. [Results] The ribotype profiles of the isolates were compared with the reference DuPont identification database. Only 2 isolates of ATCC15947 and BYK00685 matched the patterns of DuPont Identification Library with a similarily >0.85, reached 0.95 and 0.90. Altogether, 21 different ribotypes (RTs) were generated. There were geographical differences between the RTs, E. tarda isolates collected from host in Northern China were phylogenetically from isolates from Southern China were clustered into two distinct clades, all isolates collected from human and other fishes belonged to third clade. [Conclusion] The discrimination power of automated ribotyping can be used to characterize bacterial isolates of various speices for epidemiological studies.

Abstract:[Objective] To identify one endophytic strain longA which was isolated from healthy apple tree branches and study its antifungal mechanism. [Methods] Strain longA was identified based on the biochemical characteristics and 16S rRNA gene sequence analysis. The inhibitory efficiency of longA on the hyphal growth and conidial germination of V. mali were investigated by confrontation culture on slides. [Results] Strain longA was defined as Bacillus amyloliquefaciens. It could reduce the germination rate of spore and induce changes of mycelia morphology of V. mali significantly, such as deformity, branch increasing and cytoplasm exosmosis. Strain longA was aerobic. It could use glucose, sucrose, mannitol, lactic acid and citric acid as carbon source. Tolerates concentrations of NaCl up to 7%. Catalase reaction was positive. It could reduce nitrate, liquefy gelatin and degrade starch. It could not use citrate as the sole carbon source for growth. V-P test was negative. [Conclusion] Strain longA showed a certain potential of bio-control in the inhibition of V. mali.

Abstract:Corynebacterium glutamicum (C. glutamicum) is one of important industrial microbe and its genome codes for seven sigma (σ) factors of RNA polymerase. Except σA, six other σ are alternative σ factors. The regulation of gene expression mediated by σ factors is the important part of the regulatory network of bacteria. Therefore, the research on the function and regulatory mechanism of σ factors are helpful to improve the gene regulatory network of C. glutamicum and further perfect optimizing strategy of stains in the industrial production. This paper reviews the function and regulatory mechanism of six alternative σ factors in C. glutamicum and discusses several experimental designing problems noticed in the course of studying on the function of alternative σ factors. Moreover, we also present practical application value of alternative σ factors and its future research direction for continuation. This review will provide reference for further improvement of the gene regulatory network and standardization study of alternative σ in C. glutamicum.

Abstract:The dideoxy chain-termination method, which was invented in 1977 by Sanger, has opened the door of DNA sequencing. The sequencing technology has continuously advanced during the past 30 years. Each new technology has unique advantages over the previous generation, but it also has its own limitations. The key is to recognize well both the advantages and disadvantages of each technology so that it can be used reasonably. The third generation sequencing technology is a new technology with many advantages, such as high throughput, fast speed, long read and low cost. Additionally, its emergence has advanced the study of genomics, transcriptomics, epigenomics and so on. In this review, the principle of the third generation sequencing technology is introduced, followed by a summary of its application to microbial research, and its potential uses in other areas.

Abstract:Monascus pigments (MPs) are main secondary metabolites produced by Monascus sp. which has been used as food colorant for more than one thousand years. Glycerol, especially produced in process of biodiesel, could be utilized by microorganisms, such as Monascus sp. for improving MPs production. In this paper, the MPs production utilizing glycerol and its mechanism were reviewed.

Abstract:The present study investigated the differences in syllabus, teaching methodology, practice, and learning assessment for Microbiology course designed for Food Science undergraduate between Nanchang University (NCU) in China and University of Minnesota (UMN) in the US. The study found that, compared with UMN Microbiology course, NCU Microbiology course involves little advanced contents, lacks of classroom discussion, and mainly relies on final exam for learning evaluation. NCU students tend to spend time to study only before exams, which limits their full understanding of the subjects being taught and does not favor long-term knowledge retention. In addition, their ability to apply knowledge to solving real problems is poor due to lack of practice. Based on the findings of this study, it is recommend that we redesign our syllabus so that it is student-centered, renovate our course materials in order to implement the student-center syllabus and to include updated knowledge in the field, adopt problem-base learning methodology, enhance cases studies, adopt teaching assistant policy, improve learning assessment, and invest in instructor engineering training programs.

Abstract:Microbial pharmaceutics is one of the key curricula for the students of life sciences related majors. How to effectively construct the qualified curriculum system on microbial pharmaceutics is a thought-provoking project during the high-speed development of biotechnology for the faculties teaching such curriculum. In this report, we briefly addressed some helpful explorations and attempts on innovations and applications for the teaching of microbial pharmaceutics from the aspects of contents and concepts as well.

Abstract:[Objective] A new subcellular location prediction algorithm is proposed that provides basis for further experimental study of protein biological function. [Methods] Nearest neighbor classification algorithm improved by Blast comparison is used to predict the protein subcellular locations by three sequence features including amino acid composition, two peptides and pseudo amino acid composition of protein sequence. [Results] Through Jackknife test, on data set CH317 the success rates of 3 characteristics were 91.5%, 91.5% and 89.3%, on data set ZD98 success rates were 93.9%, 92.9% and 89.8%. [Conclusion] K-Nearest Neighbor algorithm improved by Blast comparison is an effective method for predicting subcellular locations of proteins.

Abstract:[Objective] A method to detect live Listeria monocytogenes cells was researched in the paper. [Methods] Propidium monoazide (PMA) permeated in the injured cells which were treated by sodium deoxycholate (SD), then PMA and DNA conducted covalent cross-linking reaction. Finally, bacterial genome DNA was extracted to detect by ddPCR. [Results] 0.1% SD and 5.0 mg/L PMA could inhibit the DNA PCR amplification of 108 CFU/mL dead L. monocytogenes cells. Only live L. monocytogenes cells were detected by SD-PMA-ddPCR even in the existence of dead L. monocytogenes cells in the chicken. The detection limit is 2.0 copies/20 μL. SD-PMA-ddPCR showed better accuracy and stability. [Conclusion] SD-PMA-ddPCR showed huge potential in foodborne pathogenic bacteria detection.