• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1863-1870
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• 2015

Fibrinolytic enzyme genes (aprE2, aprE176, and aprE179) were introduced into the Bacillus subtilis 168 chromosome without any antibiotic resistance gene. An integration vector, pDG1662, was used to deliver the genes into the amyE site of B. subtilis 168. Integrants, SJ3-5nc, SJ176nc, and SJ179nc, were obtained after two successive homologous recombinations. The integration of each fibrinolytic gene into the middle of the amyE site was confirmed by phenotypes (Amy-, Spec^S) and colony PCR results for these strains. The fibrinolytic activities of the integrants were higher than that of B. subtilis 168 by at least 3.2-fold when grown in LB broth. Cheonggukjang was prepared by inoculating each of B. subtilis 168, SJ3-5nc, SJ176nc, and SJ179nc, and the fibrinolytic activity of cheonggukjang was 4.6 ± 0.7, 10.8 ± 0.9, 7.0 ± 0.6, and 8.0 ± 0.2 (U/g of cheonggukjang), respectively at 72 h. These results showed that construction of B. subtilis strains with enhanced fibrinolytic activities is possible by integration of a strong fibrinolytic gene via a marker-free manner.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.14-20
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• 2000

The transformation of Bacillus subtilis K-54 and J-10 was carried out with constructed vectors containing structure and enhancer genes of aprN and prtR, to increase their fibrinolytic enzyme activity. Bands for the aprN and prtR genes were identified from B. subtilis J-10 by PCR that was carried out with the constructed primers for the genes. In addition, the gene fragments contained promoter site based on the results of analysing their nucleotide sequence. The two gene fragments, aprN and prtR, obtained by the PCR, were, then, inserted to vector such as T-vector and E.coli/Bacillus shuttle vector. The constructed vector were designated as pAPR2 (aprN), pENC2 (prtR) and pFLA1 (aprN and prtR), respectively. The constructed vector was used for transformation of the strains of B.subtilis J-10 and B. subtilis K-54 and the fribrinolytic activity of the transformed strains was investigated. The introduction of the vector, pAPR2 and the fibrinolytic activity of the transformed strains was investigated. The introduction of the vector, pAPR2 and pFLA1, resulted in the increase of fibrinolyitic enzyme activity in B. subtilis J-10 by 27.3% and 16%, respectively. However, the introduction of pENC2 to B. subtilis J-10 did not seem to induce increase of the enzyme activity. The strain of B.subtilis K-54 transformed with pENC2 showed an increased fibrinolytic activity by 5 folds compared with that of the original strain of B. subtilis K-54.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.800-807
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• 2022

Four aprE genes encoding alkaline serine proteases from B. subtilis strains were used as template genes for family gene shuffling. Shuffled genes obtained by DNase I digestion followed by consecutive primerless and regular PCR reactions were ligated with pHY300PLK, an E. coli-Bacillus shuttle vector. The ligation mixture was introduced into B. subtilis WB600 and one transformant (FSM4) showed higher fibrinolytic activity. DNA sequencing confirmed that the shuffled gene (aprEFSM4) consisted of DNA mostly originated from either aprEJS2 or aprE176 in addition to some DNA from either aprE3-5 or aprESJ4. Mature AprEFSM4 (275 amino acids) was different from mature AprEJS2 in 4 amino acids and mature AprE176 in 2 amino acids. aprEFSM4 was overexpressed in E. coli BL21 (DE3) by using pET26b(+) and recombinant AprEFSM4 was purified. The optimal temperature and pH of AprEFSM4 were similar to those of parental enzymes. However, AprEFM4 showed better thermostability and fibrinogen hydrolytic activity than the parental enzymes. The results indicated that DNA shuffling could be used to improve fibrinolytic enzymes from Bacillus sp. for industrial applications.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.513-521
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• 2005

A bacterium producing five fibrinolytic isozymes was isolated from black bean chung kuk. The bacterium was identified as Bacillus subtilis BB-1 by 16s rDNA sequence homology search. A gene out of five fibrinolytic genes in the Bacillus subtilis BB-1 was cloned by shot-gun method. A Cla I DNA fragment of B. subtilis BB-1 chromosome was cloned in to pBluescript II SK(-) and showed the fibrinolytic activity to bacterial cells. The Cla I DNA fragment was sequenced and the sequences did not show homology with gene for protease or fibrinolytic enzyme genes in other organisms. The Cla I DNA fragment was reduced to 2,142 bp by activity-guided PCR cloning method. The optimum pH and temperature of the enzyme were 5.0 and $35^{\circ}C$, respectively. Substrate specificity of the fibrinolytic enzyme was detected in skim milk, casein, gelatin and blood agar plates. The activity of the enzyme was not detected with these substrates. Taken together, this enzyme is a new fibrinolytic enzyme and may be used to prevent thrombosis and arteriosclerosis.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.439-446
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• 2020

Two Bacillus strains, K3 and K208, both demonstrating strong fibrinolytic activities were isolated from Kimchi, a traditional Korean preparation of fermented vegetables. Isolates were subjected to various molecular biology based identification methods including RAPD-PCR and identified as B. subtilis and B. velezensis, respectively. Tryptic soy broth (TSB) was found to best maintain both the growth and the fibrinolytic activity of these strains. Culture supernatants were analyzed by SDS-PAGE and fibrin zymography, and the results indicate that a 40 and 27 kDa band seem to be responsible for the fibrinolytic activities of these two isolates and the 27 kDa band was subsequently identified as the mature form of AprE, the major fibrinolytic enzyme. Thus the aprE genes were cloned and the translated amino acid sequences demonstrated 99.3% identity with each other, and 86.5% identity with BsfA, a fibrinolytic enzyme from B. subtilis ZA400 also isolated from Kimchi, and AprE2, a fibrinolytic enzyme from B. subtilis CH3-5 isolated from Cheonggukjang, a traditional Korean fermented soy. Given this B. subtilis K3 and B. velezensis K208 may be promising starter cultures in the production of fermented foods.

• Journal of Microbiology and Biotechnology
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• v.31 no.6
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• pp.833-839
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• 2021

Bacillus subtilis CH3-5 isolated from cheonggukjang secretes a 28 kDa protease with a strong fibrinolytic activity. Its gene, aprE3-5, was cloned and expressed in a heterologous host (Jeong et al., 2007). In this study, the promoter of aprE3-5 was replaced with other stronger promoters (P_cry3A, P₁₀, P_SG1, P_srfA) of Bacillus spp. using PCR. The constructed chimeric genes were cloned into pHY300PLK vector, and then introduced into B. subtilis WB600. The P10 promoter conferred the highest fibrinolytic activity, i.e., 1.7-fold higher than that conferred by the original promoter. Overproduction of the 28 kDa protease was confirmed using SDS-PAGE and fibrin zymography. RT-qPCR analysis showed that aprE3-5 expression was 2.0-fold higher with the P10 promoter than with the original promoter. Change of the initiation codon from GTG to ATG further increased the fibrinolytic activity. The highest aprE3-5 expression was observed when two copies of the P₁₀ promoter were placed in tandem upstream of the ATG initiation codon. The construct with P10 promoter and ATG and the construct with two copies of P10 promoter in tandem and ATG exhibited 117% and 148% higher fibrinolytic activity, respectively, than that exhibited by the construct containing P10 promoter and GTG. These results confirmed that significant overproduction of a fibrinolytic enzyme can be achieved by suitable promoter modification, and this approach may have applications in the industrial production of AprE3-5 and related fibrinolytic enzymes.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.9-18
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• 2017

Nine bacilli with fibrinolytic activities were isolated from doenjang, a traditional Korean fermented soy food. Among them, RSB34 showed the strongest activity and was identified as Bacillus amyloliquefaciens by 16S rRNA and recA gene sequencing. During growth on LB up to 96 h, RSB34 showed the highest fibrinolytic activity ($83.23mU/{\mu}l$) at 48 h. Three bands of 23, 27, and 42 kDa in size were observed when the culture supernatant was analyzed by SDS-PAGE and 27 and 42 kDa bands by fibrin zymography. The gene encoding the 27 kDa fibrinolytic enzyme AprE34 was cloned by PCR. BLAST analyses confirmed that the gene was a homolog to genes encoding AprE-type proteases. aprE34 was overexpressed in Escherichia coli BL21(DE3) using pET26b(+). Recombinant AprE34 was purified and examined for its properties. The $K_m$ and $V_{max}$ values of recombinant AprE34 were $0.131{\pm}0.026mM$ and $16.551{\pm}0.316{\mu}M/l/min$, respectively, when measured using an artificial substrate, N-succinyl-ala-ala-pro-phe-p-nitroanilide. aprE34 was overexpressed in B. subtilis WB600 using pHY300PLK. B. subtilis transformants harboring pHYRSB34 (pHY300PLK with aprE34) showed higher fibrinolytic activity than B. amyloliquefaciens RSB34.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.274-281
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• 2006

A fibrinolytic enzyme gene was isolated from Bacillus subtilis BB-1 by PCR method. Primers for PCR cloning were designed according to pre-identified gene for fibrinolytic enzymes from B. subtilis. The primer sequences were 5'-CGG ATC CGT GAG AGG CAA AAA GGT G-3' and 5'-TGA ATT CTT AAT GTG CTG CTG CTT GTC C-3' as concensus sequences of the fibrinolytic genes of Bacillus species. The PCR product was 1,145 bp and the sequence homology was 99% with nattokinase gene isolated from Japanese natto. The cloned fibrinolytic gene was reconstructed in Bacillus-E. coli shuttle vector, pEB for bulk-production. The fibrinolytic enzyme was purified by FPLC from the cloned B. subtilis 168. The optimum pH and temperature of the enzyme were 7.0 and $35^{\circ}C$, respectively. The fibrinolytic enzyme did not show any activity toward to skim milk, gelatin, casein and blood agar plate. The enzyme specific polyclonal antibody was prepared in rabbit for further assays such as detection of the gene expression in plant cells. This means that the enzyme may be used for health-care such as thrombosis without any hamful effects in the blood vessel.

• Journal of Life Science
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• v.23 no.2
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• pp.259-266
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• 2013

To isolate the fibrinolytic enzyme, 268 strains from 21 samples were morphologically isolated from Cheonggukjang collected from Korea and Japan. Among the 268 strains, protease-producing bacteria were isolated in nutrient agar medium including 1% skimmed milk. As a result of this, 22 strains were isolated. Apiweb site was used to identify these strains based on their biochemical properties. In addition, 16S rRNA sequencing was performed to identify the strain. Most of the identified strains were Bacillus subtilis and B. amyloliquefaciens. Fibrinolytic enzyme activity was measured with the fibrin plate method. Five strains were finally selected: A2-14, A2-20, C1-05, C1-09, and F2-01. Of those five strains, the A2-20 strain, which is close to B. amyloliquefaciens, showed the strongest fibrinolytic activity. The fibrinolytic enzyme produced by the A2-20 strain was partially purified from culture supernatant by gel filtration and ion exchange chromatography. The optimal pH and temperature values of the partially purified enzyme were 7.0 and $35^{\circ}C$, respectively. Purified protein analysis was carried out with SDS-PAGE and zymography. A genetic analysis was also conducted by PCR based on the consensus sequence of fibrinolytic enzyme. Corresponding genes with a partial sequence of the A2-20 strain were identified.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.72-79
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• 2005

A new Bacillus peptidase, bacillopeptidase DJ-2 (bpDJ-2), with molecular mass of 42 kDa and isoelectric point (pI) of 3.5- 3.7, was purified to homogeneity from Bacillus sp. DJ-2 isolated from Doen-Jang, a traditional Korean soybean fermented food. The enzyme was identified as an extracellular serine fibrinolytic protease. The optimal conditions for the reaction were pH 9.0 and $60^{\circ}C$. The first 18 amino acid residues of the N-terminal amino acid sequence of bpDJ-2 were TDGVEWNVDQIDAPKAW, which is identical to that of bacillopeptidase F (bpf). However, based on their Nterminal amino acid sequence, molecular size, and pI, it is different from that of bpf and extracellular 90 kDa. The whole (2,541 bp, full-bpDJ-2) and mature (1,956 bp, mature-bpDJ-2) genes were cloned, and its nucleotide sequence and deduced amino acid sequence were determined. The expressed proteins, full-bpDJ-2 and mature-bpDJ-2, were detected on SDSPAGE at expected sizes of 92 and 68 kDa, respectively.