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Explore effective way to increase acid resistance of lactococcus lactis F44 for higher production of nisin. Reporter: 冯文婧. Background. Nisin is a 34-amino acid antimicrobial peptide with various unusual amino acids and five ring structures. Broad host spectrum. easily being digested. - PowerPoint PPT Presentation
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Explore effective way to increase acid resistance of lactococcus lactis F44 for higher production of nisin
Reporter: 冯文婧
Background
• Nisin is a 34-amino acid antimicrobial peptide with various unusual amino acids and five ring structures
Broad host spectrum
easily being digested
preservative
limitation for higher production
Non-appropriate pH value Nisin degrades quickly when pH value higher than
4.0 (data not shown)
Degradation from Protease
The contradiction between the optimum
growth pH (7.2) of L.lactis and stability of
nisin(pH2.0).
Improve acid resistance of L.lactis by transforming acid tolerance genes
Acid tolerance response (ATR)
Strains Acid resistance gene Function Positive effects (P) /negative effects (N)
Escherichia. coli relA ,relQ (p)ppGpp synthase for stringent response P
Pseudomonas aeruginosa relA spoT (p)ppGpp synthase for stringent response P
Lactococcus.lactis relA ,relQ (p)ppGpp synthase for stringent response P
Cell membrane changes
Lactococcus.lactisphospholipid acyl
desaturaseProvide substrate for cfa enzyme and enhance
rigidity of the cell membraneP
Lactococcus.lactis; Lactobacillus helveticus; Oenococcus oeni
cfacyclopropane synthase, enhance rigidity of the
cell membraneP
Lactococcus.lactis ugpAA permease for sn-glycerol-3-phsophate
transport systemP
S.mutans dltC encode D-alanyl carrier protein(Dcp) P
Lactococcus.lactis guaA purine biosynthesis P
Escherichia. coli yidCinner membrane protein for insertion, folding
and quality control of the inner membrane proteins
P
Listeria monocytogenes thiT thiamine uptake system P
proton consumption by decarboxylase effect
Escherichia. coli gadA; gadB; gadCglutamate decarboxylase system to consume
surplus protonP
L.casei mleS, mleP, mleR Malolactic fermentation effect P
Proton pumps
Megasphaera elsdenii, Streptococcus bovis atpEBFHAGDC Proton extrusion activity P
L.casei atpA,atpD,atpG Proton extrusion activity P
Alkali formation
E.coli, listeria monocytogenes, L.casei arcA, arcB, arcC, arcD Arginine deiminase system P
L.casei argG convert aspartate to L-argino-succinate P
L.casei asnA Convert aspartate to asparagine N
S. salivarius ureC, ureB, ureA Apoenzymes of urease P
S. salivarius ureD, ureE, ureF, ureGaccessory proteins to assist the incorporation of
the nickel ions into the enzymeP
S. salivarius ureI Sensor and regulator P
Protection from macromolecules
L.lactisgrpE GroE, groL, dnaK,
groS, hslO, Clp, clpXchaperones P
Escherichia. coli gshA , gshB Related glutathione synthesized genes P
Escherichia. coli hdeA, hdeB Periplasmic acid stress protein P
L.lactis trePP, pgmB Related trehalose synthases P
Escherichia. coli, Propionibacterium freudenreichii
ostA, ostB Related trehalose synthases P
L.casei hisM permease of the histidine transport system P
Enhancing cell wall
M.tuberculosis arfA, arfB, arfCammonia release facilitator and peptidoglycan
linker proteinP
Regulators
Escherichia. coli EvgS/EvgA, PhoQ/PhoP, TCSs P
Escherichia. coli safA, iraM The connector of the TCSs P
Escherichia. coli YdeO, GadE Related TCSs proteins P
Review about acid resistance genes
Acid tolerance response (ATR)
Strains Acid resistance gene Function Positive effects (P) /negative effects (N)
Escherichia. coli relA ,relQ (p)ppGpp synthase for stringent response P
Pseudomonas aeruginosa relA spoT (p)ppGpp synthase for stringent response P
Lactococcus.lactis relA ,relQ (p)ppGpp synthase for stringent response P
Cell membrane changes
Lactococcus.lactisphospholipid acyl
desaturaseProvide substrate for cfa enzyme and enhance
rigidity of the cell membraneP
Lactococcus.lactis; Lactobacillus helveticus; Oenococcus oeni
cfacyclopropane synthase, enhance rigidity of the
cell membraneP
Lactococcus.lactis ugpAA permease for sn-glycerol-3-phsophate
transport systemP
S.mutans dltC encode D-alanyl carrier protein(Dcp) P
Lactococcus.lactis guaA purine biosynthesis P
Escherichia. coli yidCinner membrane protein for insertion, folding
and quality control of the inner membrane proteins
P
Listeria monocytogenes thiT thiamine uptake system P
proton consumption by decarboxylase effect
Escherichia. coli gadA; gadB; gadCglutamate decarboxylase system to consume
surplus protonP
L.casei mleS, mleP, mleR Malolactic fermentation effect P
Proton pumps
Megasphaera elsdenii, Streptococcus bovis atpEBFHAGDC Proton extrusion activity P
L.casei atpA,atpD,atpG Proton extrusion activity P
Alkali formation
E.coli, listeria monocytogenes, L.casei arcA, arcB, arcC, arcD Arginine deiminase system P
L.casei argG convert aspartate to L-argino-succinate P
L.casei asnA Convert aspartate to asparagine N
S. salivarius ureC, ureB, ureA Apoenzymes of urease P
S. salivarius ureD, ureE, ureF, ureGaccessory proteins to assist the incorporation of
the nickel ions into the enzymeP
S. salivarius ureI Sensor and regulator P
Protection from macromolecules
L.lactisgrpE GroE, groL, dnaK,
groS, hslO, Clp, clpXchaperones P
Escherichia. coli gshA , gshB Related glutathione synthesized genes P
Escherichia. coli hdeA, hdeB Periplasmic acid stress protein P
L.lactis trePP, pgmB Related trehalose synthases P
Escherichia. coli, Propionibacterium freudenreichii
ostA, ostB Related trehalose synthases P
L.casei hisM permease of the histidine transport system P
Enhancing cell wall
M.tuberculosis arfA, arfB, arfCammonia release facilitator and peptidoglycan
linker proteinP
Regulators
Escherichia. coli EvgS/EvgA, PhoQ/PhoP, TCSs P
Escherichia. coli safA, iraM The connector of the TCSs P
Escherichia. coli YdeO, GadE Related TCSs proteins P
Overexpressing genes underlined in blue circle, to verify the influence these exert on nisin production
Screening for genes based on nisin production
Our goal
