Displaying publications 1 - 20 of 42 in total

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  1. Mohd Rasid NH, Abdul Halid N, Song AA, Sabri S, Saari N, Hasan H
    Mol Biotechnol, 2023 Jun;65(6):861-870.
    PMID: 36273370 DOI: 10.1007/s12033-022-00584-z
    There is an increasing demand for natural food preservatives due to consumers' concern on the negative effects of chemical preservatives in food products. Nisin (bacteriocin) is an effective food biopreservative that has been approved globally. However, its low yield proves to be a limiting factor and must be addressed to meet the increasingly high demand from the food industry. The present work thus investigated the effects of individual and combined fermentation factors on Lactococcus lactis ATCC 11454 growth and nisin activity using the one-factor-at-a-time (OFAT) method. The level of each factor that gave the highest nisin production was then selected and combined to further improve its activity. The best combined conditions for highest cell growth and nisin activity were 30 °C, pH 6.0, and mild agitation with the addition of 1.0% w/v glucose, 1.0% w/v skim milk, and 0.5% v/v Tween 20. This increased nisin production by 22.7% as compared to control (basic condition). The present work provided critical information on the relationship between fermentation conditions, growth, and nisin activity of L. lactis ATCC 11454 that could be explored to understand the potential and limitation of the strain. This fermentation strategy can also serve as a benchmark to further enhance the production of bacteriocin or other biopreservative compounds.
    Matched MeSH terms: Lactococcus lactis*
  2. Yap TW, Rabu A, Abu Bakar FD, Rahim RA, Mahadi NM, Illias RM, et al.
    ScientificWorldJournal, 2014;2014:642891.
    PMID: 24982972 DOI: 10.1155/2014/642891
    Lactococcus lactis is the most studied mesophilic fermentative lactic acid bacterium. It is used extensively in the food industry and plays a pivotal role as a cell factory and also as vaccine delivery platforms. The proteome of the Malaysian isolated L. lactis M4 dairy strain, obtained from the milk of locally bred cows, was studied to elucidate the physiological changes occurring between the growth phases of this bacterium. In this study, ultraperformance liquid chromatography nanoflow electrospray ionization tandem mass spectrometry (UPLC- nano-ESI-MS(E)) approach was used for qualitative proteomic analysis. A total of 100 and 121 proteins were identified from the midexponential and early stationary growth phases, respectively, of the L. lactis strain M4. During the exponential phase, the most important reaction was the generation of sufficient energy, whereas, in the early stationary phase, the metabolic energy pathways decreased and the biosynthesis of proteins became more important. Thus, the metabolism of the cells shifted from energy production in the exponential phase to the synthesis of macromolecules in the stationary phase. The resultant proteomes are essential in providing an improved view of the cellular machinery of L. lactis during the transition of growth phases and hence provide insight into various biotechnological applications.
    Matched MeSH terms: Lactococcus lactis/genetics; Lactococcus lactis/growth & development*; Lactococcus lactis/metabolism*
  3. Jawan R, Abbasiliasi S, Mustafa S, Kapri MR, Halim M, Ariff AB
    Probiotics Antimicrob Proteins, 2021 04;13(2):422-440.
    PMID: 32728855 DOI: 10.1007/s12602-020-09690-3
    Determination of a microbial strain for the joining into sustenance items requires both in vitro and in vivo assessment. A newly isolated bacteriocin-like inhibitory substance (BLIS) producing lactic acid bacterium, Lactococcus lactis Gh1, was isolated from a traditional flavour enhancer and evaluated in vitro for its potential applications in the food industry. Results from this study showed that L. lactis was tolerant to NaCl (≤ 4.0%, w/v), phenol (≤ 0.4%, w/v), 0.3% (w/v) bile salt, and pH 3. BLIS from L. lactis showed antimicrobial activity against Listeria monocytogenes ATCC 15313 and was susceptible to 10 types of antibiotics. The absence of haemolytic activity and the presence of acid phosphatase and naphthol-AS-BI-phosphohydrolase were observed in L. lactis. L. lactis could coagulate milk and showed a negative response to amylolytic and proteolytic activities and did not secrete β-galactosidase. The antimicrobial activity of BLIS was completely abolished at 121 °C. The BLIS was conserved at 4 °C in BHI and MRS medium up to 6-4 months, respectively. BLIS activity was more stable in BHI as compared to MRS after four freeze-thaw cycles and was not affected by a wide range of pH (pH 4-8). BLIS was sensitive to proteinase k and resistant to catalase and trypsin. The antimicrobial activity was slightly reduced by acetone, ethanol, methanol, and acetonitrile at 10% (v/v) and also towards Tween-80, urea, and NaCl 1% (v/v). Results from this study have demonstrated that L. lactis has a vast potential to be applied in the food industry, such as for the preparation of starter culture, functional foods, and probiotic products.
    Matched MeSH terms: Lactococcus lactis*
  4. Koko I, Song AA, Masarudin MJ, Abdul Rahim R
    BMC Biotechnol, 2019 11 27;19(1):82.
    PMID: 31775775 DOI: 10.1186/s12896-019-0575-x
    BACKGROUND: Site-specific integration system allows foreign DNA to be integrated into the specific site of the host genome, enabling stable expression of heterologous protein. In this study, integrative vectors for secretion and surface display of proteins were constructed based on a lactococcal phage TP901-1 integrating system.

    RESULTS: The constructed integration system comprises of a lactococcal promoter (PnisA or P170), phage attachment site (attP) from bacteriophage TP901-1, a signal peptide (USP45 or SPK1) for translocation of the target protein, and a PrtP344 anchor domain in the case of the integrative vectors for surface display. There were eight successfully constructed integrative vectors with each having a different combination of promoter and signal peptide; pS1, pS2, pS3 and pS4 for secretion, and pSD1, pSD2, pSD3 and pSD4 for surface display of desired protein. The integration of the vectors into the host genome was assisted by a helper vector harbouring the integrase gene. A nuclease gene was used as a reporter and was successfully integrated into the L. lactis genome and Nuc was secreted or displayed as expected. The signal peptide SPK1 was observed to be superior to USP45-LEISSTCDA fusion in the secretion of Nuc. As for the surface display integrative vector, all systems developed were comparable with the exception of the combination of P170 promoter with USP45 signal peptide which gave very low signals in whole cell ELISA.

    CONCLUSION: The engineered synthetic integrative vectors have the potential to be used for secretion or surface display of heterologous protein production in lactococcal expression system for research or industrial purposes, especially in live vaccine delivery.

    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism; Lactococcus lactis/virology*
  5. Raftari M, Ghafourian S, Bakar FA
    J Dairy Res, 2013 Nov;80(4):490-5.
    PMID: 24063299 DOI: 10.1017/S0022029913000435
    The dairy industry uses lipase extensively for hydrolysis of milk fat. Lipase is used in the modification of the fatty acid chain length, to enhance the flavours of various chesses. Therefore finding the unlimited source of lipase is a concern of dairy industry. Due to the importance of lipase, this study was an attempt to express the lipase from Burkholderia cepacia in Lactococcus lactis. To achieve this, a gene associated with lipase transport was amplified and subcloned in inducible pNZ8148 vector, and subsequently transformed into Lc. lactis NZ9000. The enzyme assay as well as SDS-PAGE and western blotting were carried out to analysis the recombinant lipase expression. Nucleotide sequencing of the DNA insert from the clone revealed that the lipase activity corresponded to an open reading frame consisting of 1092 bp coding for a 37·5-kDa size protein. Blue colour colonies on nile blue sulphate agar and sharp band on 37·5-kD size on SDS-PAGE and western blotting results confirm the successful expression of lipase by Lc. lactis. The protein assay also showed high expression, approximately 152·2 μg/ml.h, of lipase by recombinant Lc. lactis. The results indicate that Lc. lactis has high potential to overproduce the recombinant lipase which can be used commercially for industrially purposes.
    Matched MeSH terms: Lactococcus lactis/enzymology*; Lactococcus lactis/genetics; Lactococcus lactis/metabolism
  6. Loh JY, Kay GL, Ting ASY
    Mar Biotechnol (NY), 2018 Jun;20(3):353-362.
    PMID: 29654379 DOI: 10.1007/s10126-018-9813-9
    Predominance of beneficial bacteria helps to establish a healthy microbiota in fish gastrointestinal system and thus to reduce emerging pathogen. In this study, the colonization efficacy of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana and its potential as a probiotic in suppressing Edwardsiella sp. infection were investigated in vivo. The colonization extent of the bioencapsulated L. lactis was established through visualization of gfp gene-transformed L. lactis in A. franciscana. Here, we demonstrate that when A. franciscana is administrated with L. lactis at 108 CFU mL-1 for 8 h, the highest relative percentage of survival (RPS = 50.0) is observed after inoculation with Edwardsiella sp. The total counts of L. lactis entrapped in Artemia were the highest (ranged from 3.2 to 5.1 × 108 CFU mL-1), when 108-109 CFU mL-1 of L. lactis was used as starting inoculum, with the bioencapsulation performed within 8-24 h. Fluorescent microscopy showed gfp-transformed L. lactis colonized the external trunk surfaces, mid-gut and locomotion antennules of the A. franciscana nauplii. These illustrations elucidate the efficiency of colonization of L. lactis in the gastrointestinal tract and on the body surfaces of Artemia. In conclusion, L. lactis subsp. lactis CF4MRS shows a good efficacy of colonization in Artemia and has the potential for biocontrol/probiotic activity against Edwardsiella sp. infection.
    Matched MeSH terms: Lactococcus lactis/physiology*
  7. Noreen N, Hooi WY, Baradaran A, Rosfarizan M, Sieo CC, Rosli MI, et al.
    Microb Cell Fact, 2011;10:28.
    PMID: 21518457 DOI: 10.1186/1475-2859-10-28
    Many plasmid-harbouring strains of Lactococcus lactis have been isolated from milk and other sources. Plasmids of Lactococcus have been shown to harbour antibiotic resistance genes and those that express some important proteins. The generally regarded as safe (GRAS) status of L. lactis also makes it an attractive host for the production of proteins that are beneficial in numerous applications such as the production of biopharmaceutical and nutraceutical. In the present work, strains of L. lactis were isolated from cow's milk, plasmids were isolated and characterised and one of the strains was identified as a potential new lactococcal host for the expression of heterologous proteins.
    Matched MeSH terms: Lactococcus lactis/growth & development; Lactococcus lactis/isolation & purification; Lactococcus lactis/metabolism*
  8. Bayat O, Baradaran A, Ariff A, Mohamad R, Rahim RA
    Biotechnol Lett, 2014 Mar;36(3):581-5.
    PMID: 24185903 DOI: 10.1007/s10529-013-1390-4
    Human interferon alpha (IFN-α) was expressed in two strains of Lactococcus lactis by aid of two promoters (P32 and Pnis) giving rise to two recombinant strains: MG:IFN and NZ:IFN, respectively. The expression of IFN was confirmed by ELISA and western blotting. Highest production was achieved using glucose for growth of both recombinant strains with nisin, used for induction of the recombinant strain with Pnis promoter, at 30 ng/ml. The optimum time for MG:IFN was 9 h and for NZ:IFN was 4.5 h. The highest productions by MG:IFN and NZ:IFN were 1.9 and 2.4 μg IFN/l, respectively. Both of the expressed IFNs showed bioactivities of 1.9 × 10(6) IU/mg that were acceptable for further clinical studies.
    Matched MeSH terms: Lactococcus lactis/genetics; Lactococcus lactis/metabolism*
  9. Raha AR, Ross E, Yusoff K, Manap MY, Ideris A
    J. Biochem. Mol. Biol. Biophys., 2002 Feb;6(1):7-11.
    PMID: 12186776
    An erythromycin resistance plasmid, pAJ01 was isolated from Loctococcus lactis isolate C5 that was isolated from a healthy two-week-old chicken cecum. A 4 kb plasmid was transformed into plasmidless L. lactis MG1363 before a restriction endonuclease map was constructed. It was then fused with pUC19 to form pAJ02, which can replicate in Escherichia coli XLI-Blue as well as L. lactis MG1363. The plasmid was stably maintained in Lactococcus for more than 100 generations.
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/isolation & purification
  10. Lim SH, Jahanshiri F, Rahim RA, Sekawi Z, Yusoff K
    Lett Appl Microbiol, 2010 Dec;51(6):658-64.
    PMID: 20973806 DOI: 10.1111/j.1472-765X.2010.02950.x
    A system for displaying heterologous respiratory syncytial virus (RSV) glycoproteins on the surface of Lactococcus lactis NZ9000 was developed.
    Matched MeSH terms: Lactococcus lactis/genetics; Lactococcus lactis/metabolism*
  11. Kalyanasundram J, Chia SL, Song AA, Raha AR, Young HA, Yusoff K
    BMC Biotechnol, 2015;15:113.
    PMID: 26715153 DOI: 10.1186/s12896-015-0231-z
    The exploitation of the surface display system of food and commensal lactic acid bacteria (LAB) for bacterial, viral, or protozoan antigen delivery has received strong interest recently. The Generally Regarded as Safe (GRAS) status of the Lactococcus lactis coupled with a non-recombinant strategy of in-trans surface display, provide a safe platform for therapeutic drug and vaccine development. However, production of therapeutic proteins fused with cell-wall anchoring motifs is predominantly limited to prokaryotic expression systems. This presents a major disadvantage in the surface display system particularly when glycosylation has been recently identified to significantly enhance epitope presentation. In this study, the glycosylated murine Tyrosinase related protein-2 (TRP-2) with the ability to anchor onto the L. lactis cell wall was produced in suspension adapted Chinese Hamster Ovary (CHO-S) cells by expressing TRP-2 fused with cell wall anchoring LysM motif (cA) at the C-terminus.
    Matched MeSH terms: Lactococcus lactis/genetics; Lactococcus lactis/metabolism*
  12. Raftari M, Ghafourian S, Abu Bakar F
    J Appl Microbiol, 2017 Apr;122(4):1009-1019.
    PMID: 28028882 DOI: 10.1111/jam.13388
    AIMS: This study was an attempt to create a novel milk clotting procedure using a recombinant bacterium capable of milk coagulation.

    METHODS AND RESULTS: The Rhizomucor pusillus proteinase (RPP) gene was sub-cloned into a pALF expression vector. The recombinant pALF-RPP vector was then electro-transferred into Lactococcus lactis. Finally, the milk coagulation ability of recombinant L. lactis carrying a RPP gene was evaluated. Nucleotide sequencing of DNA insertion from the clone revealed that the RPP activity corresponded to an open reading frame consisting of 1218 bp coding for a 43·45 kDa RPP protein. The RPP protein assay results indicated that the highest RPP enzyme expression with 870 Soxhlet units (SU) per ml and 7914 SU/OD were obtained for cultures which were incubated at pH 5·5 and 30°C. Interestingly, milk coagulation was observed after 205 min of inoculating milk with recombinant L. lactis carrying the RPP gene.

    CONCLUSION: The recombinant L. lactis carrying RPP gene has the ability to function as a starter culture for acidifying and subsequently coagulating milk by producing RPP as a milk coagulant agent.

    SIGNIFICANCE AND IMPACT OF THE STUDY: Creating a recombinant starter culture bacterium that is able to coagulate milk. It is significant because the recombinant L. lactis has the ability to work as a starter culture and milk coagulation agent.

    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism
  13. Baradaran A, Sieo CC, Foo HL, Illias RM, Yusoff K, Rahim RA
    Biotechnol Lett, 2013 Feb;35(2):233-8.
    PMID: 23076361 DOI: 10.1007/s10529-012-1059-4
    Fifty signal peptides of Pediococcus pentosaceus were characterized by in silico analysis and, based on the physicochemical analysis, (two potential signal peptides Spk1 and Spk3 were identified). The coding sequences of SP were amplified and fused to the gene coding for green fluorescent protein (GFP) and cloned into Lactococcus lactis pNZ8048 and pMG36e vectors, respectively. Western blot analysis indicated that the GFP proteins were secreted using both heterologous SPs. ELISA showed that the secretion efficiency of GFP using Spk1 (0.64 μg/ml) was similar to using Usp45 (0.62 μg/ml) and Spk3 (0.58 μg/ml).
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism*
  14. Subramaniam M, Baradaran A, Rosli MI, Rosfarizan M, Khatijah Y, Raha AR
    J. Mol. Microbiol. Biotechnol., 2012;22(6):361-72.
    PMID: 23295307 DOI: 10.1159/000343921
    Cyclodextrin glucanotransferase (CGTase) is an extracellular enzyme which catalyzes the formation of cyclodextrin from starch. The production of CGTase using lactic acid bacterium is an attractive alternative and safer strategy to produce CGTase. In this study, we report the construction of genetically modified Lactococcus lactis strains harboring plasmids that secrete the Bacillus sp. G1 β-CGTase, with the aid of the signal peptides (SPs) SPK1, USP45 and native SP (NSP). Three constructed vectors, pNZ:NSP:CGT, pNZ:USP:CGT and pNZ:SPK1:CGT, were developed in this study. Each vector harbored a different SP fused to the CGTase. The formation of halo zones on starch plates indicated the production and secretion of β-CGTase by the recombinants. The expression of this enzyme is shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and zymogram analysis. A band size of ∼75 kDa corresponding to β-CGTase is identified in the intracellular and the extracellular environments of the host after medium modification. The replacement of glucose by starch in the medium was shown to induce β-CGTase production in L. lactis. Although β-CGTase production is comparatively low in NZ:SPK1:CGT, the SP SPK1 was shown to have higher secretion efficiency compared to the other SPs used in this study.
    Matched MeSH terms: Lactococcus lactis/enzymology*; Lactococcus lactis/genetics*
  15. Tan EW, Tan KY, Phang LV, Kumar PV, In LLA
    PLoS One, 2019;14(7):e0219912.
    PMID: 31335895 DOI: 10.1371/journal.pone.0219912
    Vaccine administration via the oral route is preferable to parenteral routes due to ease of administration. To date, most available oral vaccines comprises of live attenuated pathogens as oppose to peptide-based vaccines due to its low bioavailability within the gastrointestinal (GI) tract. Over the years, probiotic-based peptide delivery vehicles comprising of lactic acid bacteria such as Lactococcus lactis has emerged as an interesting alternative due to its generally recognized as safe (GRAS) status, a fully sequenced genome, transient gut colonization time, and is an efficient cellular factory for heterologous protein production. However, its survivability through the GI tract is low, thus better delivery approaches are being explored to improve its bioavailability. In this study, we employ the incorporation of a double coated mucoadhesive film consisting of sodium alginate and Lycoat RS 720 film as the inner coat. The formulated film exhibits good mechanical properties of tensile strength and percent elongation for manipulation and handling with an entrapment yield of 93.14±2.74%. The formulated mucoadhesive film is subsequently loaded into gelatin capsules with an outer enteric Eudragit L100-55 coating capable of a pH-dependent breakdown above pH 5.5 to protect against gastric digestion. The final product and unprotected controls were subjected to in vitro simulated gastrointestinal digestions to assess its survivability. The product demonstrated enhanced protection with an increase of 69.22±0.67% (gastric) and 40.61±8.23% (intestinal) survivability compared to unprotected controls after 6 hours of sequential digestion. This translates to a 3.5 fold increase in overall survivability. Owing to this, the proposed oral delivery system has shown promising potential as a live gastrointestinal vaccine delivery host. Further studies involving in vivo gastrointestinal survivability and mice immunization tests are currently being carried out to assess the efficacy of this novel oral delivery system in comparison to parenteral routes.
    Matched MeSH terms: Lactococcus lactis/pathogenicity; Lactococcus lactis/physiology*
  16. Roslan AM, Mustafa Kamil A, Chandran C, Song AA, Yusoff K, Abdul Rahim R
    Biotechnol Lett, 2020 Sep;42(9):1727-1733.
    PMID: 32335791 DOI: 10.1007/s10529-020-02894-1
    OBJECTIVE: The effect of two signal peptides, namely Usp45 and Spk1 on the secretion of xylanase in Lactococcus lactis was analysed.

    RESULTS: Xylanase was successfully expressed in Lactococcus lactis. Recombinant xylanase fused to either signal peptide Usp45 or Spk1 showed halo zone on Remazol Brilliant Blue-Xylan plates. This indicated that the xylanase was successfully secreted from the cell. The culture supernatants of strains secreting the xylanase with help of the Spk1 and Usp45 signal peptides contained 49.7 U/ml and 34.4 U/ml of xylanase activity, respectively.

    CONCLUSION: Although Usp45 is the most commonly used signal peptide when secreting heterologous proteins in Lactococcus lactis, this study shows that Spk1 isolated from Pediococcus pentosaceus was superior to Usp45 in regard to xylanase protein secretion.

    Matched MeSH terms: Lactococcus lactis/genetics; Lactococcus lactis/metabolism*
  17. Song AA, In LLA, Lim SHE, Rahim RA
    Microb Cell Fact, 2017 04 04;16(1):55.
    PMID: 28376880 DOI: 10.1186/s12934-017-0669-x
    Lactococcus lactis has progressed a long way since its discovery and initial use in dairy product fermentation, to its present biotechnological applications in genetic engineering for the production of various recombinant proteins and metabolites that transcends the heterologous species barrier. Key desirable features of this gram-positive lactic acid non-colonizing gut bacteria include its generally recognized as safe (GRAS) status, probiotic properties, the absence of inclusion bodies and endotoxins, surface display and extracellular secretion technology, and a diverse selection of cloning and inducible expression vectors. This have made L. lactis a desirable and promising host on par with other well established model bacterial or yeast systems such as Escherichia coli, Saccharomyces [corrected] cerevisiae and Bacillus subtilis. In this article, we review recent technological advancements, challenges, future prospects and current diversified examples on the use of L. lactis as a microbial cell factory. Additionally, we will also highlight latest medical-based applications involving whole-cell L. lactis as a live delivery vector for the administration of therapeutics against both communicable and non-communicable diseases.
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism*
  18. Mat Isa N, Abdul Mutalib NE, Alitheen NB, Song AA, Rahim RA
    J. Mol. Microbiol. Biotechnol., 2017;27(4):246-251.
    PMID: 29055951 DOI: 10.1159/000481257
    This study demonstrates that cell wall treatment of Lactococcus lactis harbouring the internal ribosome entry site-incorporated lactococcal bicistronic vector pNZ:VIG mediated the delivery of genes into an eukaryotic cell line, DF1 cells, through bactofection. Bactofection analysis showed that the pNZ:VIG plasmid in L. lactis can be transferred into DF1 cells and that both the VP2 and gfp genes cloned in the plasmid can be transcribed and translated. The protein band relative to the Mr of VP2 protein (49 kDa) was successfully detected via Western blot analysis, while green fluorescence was successfully detected using a fluorescence microscope. The intensity of the bands detected increased for samples treated with both 1.5% (w/v) glycine and 10 μg/mL of lysozyme when compared to L. lactis treated with glycine alone and without treatment. Cell wall treatment of L. lactis with a combination of both glycine and lysozyme was not only shown to mediate plasmid transfer to DF1 cells, but also to increase the plasmid transfer efficiency.
    Matched MeSH terms: Lactococcus lactis/genetics*; Lactococcus lactis/metabolism*
  19. Azizan KA, Baharum SN, Mohd Noor N
    Molecules, 2012 Jul 03;17(7):8022-36.
    PMID: 22759915 DOI: 10.3390/molecules17078022
    Gas chromatography mass spectrometry (GC-MS) and headspace gas chromatography mass spectrometry (HS/GC-MS) were used to study metabolites produced by Lactococcus lactis subsp. cremoris MG1363 grown at a temperature of 30 °C with and without agitation at 150 rpm, and at 37 °C without agitation. It was observed that L. lactis produced more organic acids under agitation. Primary alcohols, aldehydes, ketones and polyols were identified as the corresponding trimethylsilyl (TMS) derivatives, whereas amino acids and organic acids, including fatty acids, were detected through methyl chloroformate derivatization. HS analysis indicated that branched-chain methyl aldehydes, including 2-methylbutanal, 3-methylbutanal, and 2-methylpropanal are degdradation products of isoleucine, leucine or valine. Multivariate analysis (MVA) using partial least squares discriminant analysis (PLS-DA) revealed the major differences between treatments were due to changes of amino acids and fermentation products.
    Matched MeSH terms: Lactococcus lactis/drug effects*; Lactococcus lactis/growth & development; Lactococcus lactis/metabolism*
  20. Jawan R, Abbasiliasi S, Tan JS, Kapri MR, Mustafa S, Halim M, et al.
    Microorganisms, 2021 Mar 12;9(3).
    PMID: 33809201 DOI: 10.3390/microorganisms9030579
    Bacteriocin-like inhibitory substances (BLIS) produced by Lactococcus lactis Gh1 had shown antimicrobial activity against Listeria monocytogenes ATCC 15313. Brain Heart Infusion (BHI) broth is used for the cultivation and enumeration of lactic acid bacteria, but there is a need to improve the current medium composition for enhancement of BLIS production, and one of the approaches is to model the optimization process and identify the most appropriate medium formulation. Response surface methodology (RSM) and artificial neural network (ANN) models were employed in this study. In medium optimization, ANN (R2 = 0.98) methodology provided better estimation point and data fitting as compared to RSM (R2 = 0.79). In ANN, the optimal medium consisted of 35.38 g/L soytone, 16 g/L fructose, 3.25 g/L sodium chloride (NaCl) and 5.40 g/L disodium phosphate (Na2HPO4). BLIS production in optimal medium (717.13 ± 0.76 AU/mL) was about 1.40-fold higher than that obtained in nonoptimised (520.56 ± 3.37 AU/mL) medium. BLIS production was further improved by about 1.18 times higher in 2 L stirred tank bioreactor (787.40 ± 1.30 AU/mL) as compared to that obtained in 250 mL shake flask (665.28 ± 14.22 AU/mL) using the optimised medium.
    Matched MeSH terms: Lactococcus lactis
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