• Food Science and Biotechnology
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• v.15 no.4
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• pp.595-598
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• 2006

Semi-quantitative monitoring of Lactobacillus sake and Lactobacillus plantarum, major and minor microorganisms in kimchi, respectively, and Lactobacillus paraplantarum, recently shown to be present in kimchi, was carried out by real-time polymerase chain reaction (PCR). Changes in the 3 species during kimchi fermentation were monitored by the threshold cycle ($C_T$) of real-time PCR. As fermentation proceeded at $15^{\circ}C$, the number of L. sake increased dramatically compared to those of L. plantarum and L. paraplantarum. During fermentation at $4^{\circ}C$, the growth rates of the 3 species decreased, but the proportions of L. plantarum and L. paraplantarum in the microbial ecosystem were almost constant. Considering the $C_T$ values of the first samples and the change in the $C_T$ value, the number of L. sake is no doubt greater than those of L. plantarum and L. paraplantarum in the kimchi ecosystem. L. sake seems to be one of the major microorganisms involved in kimchi fermentation, but there is insufficient evidence to suggest that L. plantarum is the primary acidifying bacterium.

• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.24-32
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• 2009

The KNUC25 strain isolated from over-fermented whole Chinese cabbage kimchi was examined for its physiological characteristics using API 50 CHL system assay and identified as Lactobacillus paraplantarum by analysis of whole-cell protein SDS-PAGE pattern assay and similarity of 16S rDNA sequence. L. paraplantarum KNUC25 had a broad antimicrobial activity spectrum from Gram positive to Gram negative bacteria. Scanning electron micrograph analysis showed that KNUC25 might attack to cell surface of indicator cells and destruction can lead to inhibition of the cell growth. The antimicrobial substance of the KNUC25 strain was stable to various degrading enzymes and at high temperature and not a plasmid-born matter. Resistance to proteolytic enzymes showed that an antimicrobial activity of KNUC25 might not be caused by proteinous substance. Maximum production of antimicrobial substance was the exponential growth phase at $30^{\circ}C$.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.428-433
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• 2005

A bacteriocin-producing lactic acid bacterium with inhibitory activity against the growth of Lactobacillus plantarum was isolated from kimchi, a traditional Korean fermented vegetable. For the identification of the isolate, its 16S rDNA was sequenced. As a result, the sequence showed $99\%$ homology with those from Lactobacillus paraplantarum, Lb. plantarum, and Lactobacillus pentosus. For further identification of the isolate, the sequence of its 16S/23S rDNA spacer region was determined, and the sequence matched perfectly with that of Lb. paraplantarum. SDS­PAGE fingerprinting of whole-cell proteins of the isolate was almost identical with that of Lb. paraplantarum. The isolation and identification of Lb. paraplantarum suggest that Lb. paraplantarum is one of the lactic acid bacteria involved in kimchi fermentation.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.247-259
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• 2008

Terminal-restriction fragment length polymorphism (T-RFLP) analysis, one of rapid culture-independent microbial community analysis methods, was used to determine the lactic acid bacterial complexity and dynamics during kimchi fermentation at $15^{\circ}C$ and $4^{\circ}C$. At both temperatures, the common presence of Leuconostoc mesenteroides, Lc. inhae, Lc. kimchi, Weissella koreensis, W. cibaria, Lactobacillus sakei, Lb. curvatus, Lb. plantarum, Lb. paraplantarum, Lb. pentosus, and Lb. brevis was predicted. Lc. citreum and Enterococcus faecalis were detected at $15^{\circ}C$ and $4^{\circ}C$, respectively. W. koreensis predominated during the mid stage of kimchi fermentation whereas lactobacilli were dominants during later stage. Lb. sakei and Lb. curvatus became dominants regardless of fermentation temperature but the growth of Lb. plantarum, Lb. paraplantarum, Lb. pentosus, and Lb. brevis was restricted at psychrophilic temperature. Some species of leuconostocs were maintained until the later stage of kimchi fermentation.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.287-296
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• 2007

A Lactobacillus paraplantarum strain producing a bacteriocin was isolated from kimchi using the spot-on-the lawn method and named L. paraplantarum C7 [15]. The bacteriocin, paraplantaricin C7, was found to inhibit certain Lactobacillus strains, including L. plantarum, L. pentosus, and L. delbrueckii subsp. lactis. It also inhibited Enterococcus faecalis, yet did not inhibit most of the other LAB (lactic acid bacteria) tested. The maximum level of paraplantaricin C7 activity was observed under the culture conditions of $25^{\circ}C$ and a constant pH of 4.5. Paraplantaricin C7 retained 90% of its activity after 10 min of treatment at $100^{\circ}C$ and remained stable within a pH range of 2-8. Based on a culture supernatant, paraplantaricin C7 was purified by DEAE-Sephacel column chromatography and $C_{18}$ reverse-phase HPLC. SDS-PAGE and activity staining were then conducted using the purified paraplantaricin C7, and its molecular mass determined to be about 3,800 Da. The 28 N-terminal amino acids from the purified paraplantaricin C7 were determined, and the structural gene encoding paraplantaricin C7, ppnC7, was cloned by PCR using degenerate primers based on the N-terminal amino acid sequence. The nucleotide sequences for ppnC7 and other neighboring orfs exhibited a limited homology to the previously reported plantaricin operon genes. Paraplantaricin C7 is a novel type II bacteriocin containing a double glycine leader sequence.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1071-1074
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• 2004

The effect of preadaptation at low temperature on cryoprotection was studied for Lactobacillus paraplantarum C7, a bacteriocin producer isolated from kimchi. L paraplantarum C7 cells in their log growth phase were incubated at $15^\circ{C}$, $10^\circ{C}$, or $5^\circ{C}$ for 2, 4, and 6 h, respectively, before being frozen at $-70^\circ{C}$. After 24 h of freezing, viable cells were counted after brief thawing. The freezing-thawing cycles were repeated three more times. Cells preadapted at $10^\circ{C}$ or $5^\circ{C}$ before freezing survived better than control cells, but preadaptation at $15^\circ{C}$ did not confer cryoprotection. Chloramphenicol addition did not destroy the cryoprotection, indicating that protein synthesis was not required for the development of cryoprotection. SDS-PAGE showed induction of a 6.5-kDa protein, a major cold-shock protein, in preadapted cells.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.822-829
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• 2007

A gene coding for phosphoketolase, a key enzyme of carbohydrate catabolism in heterofermentative lactic acid bacteria(LAB), was cloned from a Lactobacillus paraplantarum C7 and expressed in Escherichia coli. The gene is 2,502 bp long and codes for a 788-amino-acids polypeptide with a molecular mass of 88.7 kDa. A Shine-Dalgarno sequence(aaggag) and an inverted-repeat terminator sequence are located upstream and downstream of the phosphoketolase gene, respectively. The gene exhibits an identity of >52% with phosphoketolases of other LAB. The phosphoketolase of Lb. paraplantarum C7(LBPK) contains several highly conserved phosphoketolase signature regions and typical thiamine pyrophosphate(TPP) binding sites, as reported for other TPP-dependent enzymes. The phosphoketolase gene was fused to a glutathione S-transferase(GST::LBPK) gene for purification. The GST::LBPK fusion protein was detected in the soluble fraction of a recombinant Escherichia coli BL21. The GST::LBPK fusion protein was purified with a yield of 4.32mg/400ml by GSTrap HP affinity column chromatography and analyzed by N-terminal sequencing. LBPK was obtained by factor Xa treatment of fusion protein and the final yield was 3.78mg/400ml. LBPK was examined for its N-terminal sequence and phosphoketolase activity. The $K_M\;and\;V_{max}$ values for fructose-6-phosphate were $5.08{\pm}0.057mM(mean{\pm}SD)$ and $499.21{\pm}4.33{\mu}mol/min/mg$, respectively, and the optimum temperature and pH for the production of acetyl phosphate were $45^{\circ}C$ and 7.0, respectively.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.96-100
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• 2008

Diversity of lactic acid bacteria involved in 5 Korean fermented vegetables (Cot kimchi, Dongchimi, Baechu kimchi, Oisobagi, and Chonggak kimchi) was investigated using PCR-based method. PCR primer pairs targeted the recA gene were used for the detection of 7 species of lactic acid bacteria mainly found in kimchi and Lactobacillus acidophilus involved in dairy fermentation. Lactobacillus plantarum and Lactobacillus sakei were detected in all samples tested but Lactobacillus paraplantarum, Lactobacillus pentosus, and Lb. acidophilus were not detected. Lactobacillus brevis and Leuconostoc citreum were detected only from Baechu kimchi and Leuconostoc mesenteroides was detected from Got kimchi, Dongchimi, Baechu kimchi, and Oisobagi. The difference of detected species from fermented vegetables may be originated from the difference of main materials. Lb. plantarum and Lb. sakei are supposed to be broadly involved in Korean fermented vegetables.

• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1213-1216
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• 2007

The vector pCW5 with plasmid pC7, originally isolated in Lactobacillus paraplantarum C7 derived from kimchi, was constructed using a p32 strong promoter, the pC7 replicon, and green fluorescent protein (GFP) as the reporter. The constructed vector was transformed into E. coli and Leuconostoc mesenteroides, and GFP expression detected using a Western blot analysis. GFP fluorescence was recognized in E. coli and Leuconostoc mesenteroides using a confocal microscope. In addition, GFP fluorescence was also clearly detected in several industrially important lactic acid bacteria (LAB), including Lactobacillus bulgaricus, Lactobacillus paraplantarum, and Lactobacillus plantarum. Thus, pCW5 was shown to be effective for Leuconostoc mesenteroides when using GFP as the reporter, and it can also be used as a broad-host-range vector for other lactic acid bacteria.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.91-98
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• 2009

As consumption of kimchi has increased, factories have begun to produce this traditional Korean fermented vegetable dish on a large scale. Following the rise in manufacturing, the hygienic conditions under which commercial kimchi is being made have become an issue. We isolated 17 coliform bacteria from commercial kimchi that had not been fully fermented. These bacteria were partially identified as one of seven different species from three genera by 16S rDNA sequence analysis as follows: Enterobacter intermedius, Ent. cloacae, Ent. amnigenus, Klebsiella terrigena, K. ornithinolytica, K. oxytoca, and Hafnia alvei. Lactobacillus paraplantarum KNUC25 has been isolated from over-fermented Chinese cabbage kimchi and its antimicrobial activity reported in the literature. In our study, the KNUC25 strain showed antibacterial activity against isolated coliform bacteria and some pathogenic coliform bacteria through spot-on-the-lawn tests and viable cell tests. Through development and use of a cell-free supernatant of L. paraplantarum KNUC25, we effectively controlled coliform bacteria in commercial kimchi.