Improvement of multiple-stress tolerance and lactic acid production in Lactococcus lactis NZ9000 under conditions of thermal stress by heterologous expression of Escherichia coli DnaK.
The effects of nisin-induced dnaK expression in Lactococcus lactis were examined, and this expression was shown to improve stress tolerance and lactic acid fermentation efficiency. Using a nisin-inducible expression system, DnaK proteins from L. lactis (DnaK(Lla)) and Escherichia coli (DnaK(Eco)) were produced in L. lactis NZ9000. In comparison to a strain harboring the empty vector pNZ8048 (designated NZ-Vector) and one expressing dnaK(Lla) (designated NZ-LDnaK), the dnaK(Eco)-expressing strain, named NZ-EDnaK, exhibited more tolerance to heat stress at 40 degrees C in GM17 liquid medium. The cell viability of NZ-Vector was reduced 4.6-fold after 6 h of heat treatment. However, NZ-EDnaK showed 13.5-fold increased viability under these conditions, with a very low concentration of DnaK(Eco) production. Although the heterologous expression of dnaK(Eco) did not effect DnaK(Lla) production, heat treatment increased the DnaK(Lla) level 3.5- and 3.6-fold in NZ-Vector and NZ-EDnaK, respectively. Moreover, NZ-EDnaK showed tolerance to multiple stresses, including 3% NaCl, 5% ethanol, and 0.5% lactic acid (pH 5.47). In CMG medium, the lactate yield and the maximum lactate productivity of NZ-EDnaK were higher than the corresponding values for NZ-Vector at 30 degrees C. Interestingly, at 40 degrees C, these values of NZ-EDnaK were not significantly different from the corresponding values for the control strain at 30 degrees C. Lactate dehydrogenase (LDH) activity was also found to be stable at 40 degrees C in the presence of DnaK(Eco). These findings suggest that the heterologous expression of dnaK(Eco) enhances the quality control of proteins and enzymes, resulting in improved growth and lactic acid fermentation at high temperature.
Abdullah-Al-Mahin
Laboratory of Microbial Technology, Division of Microbial Science and Technology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
Sugimoto
Shinya
S
Higashi
Chihana
C
Matsumoto
Shunsuke
S
Sonomoto
Kenji
K
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001709:Biotechnology; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D019344:Lactic Acid / Q000378:metabolism*; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology*; D009561:Nisin / Q000494:pharmacology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D011994:Recombinant Proteins; D009561:Nisin; D019344:Lactic Acid; C063842:dnaK protein, E coli
Appl Environ Microbiol. 2004 Oct;70(10):5929-36
15466535
Appl Microbiol Biotechnol. 2007 Dec;77(4):909-15
17960374
Appl Environ Microbiol. 2003 Feb;69(2):917-25
12571012
Mol Microbiol. 1999 Sep;33(6):1152-61
10510230
J Mol Biol. 1965 Mar;11:476-90
14267270
J Bacteriol. 1977 Jul;131(1):82-91
17595
Appl Environ Microbiol. 2003 Aug;69(8):4951-65
12902291
Biopolymers. 2000;55(1):62-73
10931442
J Appl Microbiol. 2002;93(6):1003-11
12452956
J Dairy Sci. 2000 Apr;83(4):894-907
10791807
Mol Microbiol. 1993 Aug;9(4):671-80
7901731
Biosci Biotechnol Biochem. 2008 Mar;72(3):811-22
18323638
Curr Opin Biotechnol. 1995 Oct;6(5):494-500
7579660
J Bacteriol. 1998 Aug;180(15):3873-81
9683484
Annu Rev Microbiol. 1998;52:41-79
9891793
Annu Rev Biochem. 1986;55:1151-91
2427013
Appl Environ Microbiol. 2003 Apr;69(4):2044-51
12676681
J Biosci Bioeng. 2008 Oct;106(4):324-36
19000607
J Bacteriol. 1989 May;171(5):2337-46
2651398
Acta Biochim Pol. 2007;54(3):509-22
17882322
Curr Microbiol. 2001 Nov;43(5):346-50
11688799
Curr Opin Microbiol. 1999 Apr;2(2):148-52
10322169
Appl Environ Microbiol. 1997 May;63(5):1826-37
9143115
Nature. 1991 Mar 14;350(6314):165-7
2005967
J Bacteriol. 1991 Jul;173(14):4404-10
2066337
Annu Rev Genet. 1984;18:295-329
6442118
Mol Microbiol. 1995 Feb;15(3):421-9
7540247
Appl Environ Microbiol. 1997 May;63(5):1953-8
9143127
J Bacteriol. 1997 Feb;179(4):1153-64
9023197
Appl Environ Microbiol. 1989 Dec;55(12):3119-23
16348073
Appl Environ Microbiol. 1996 Oct;62(10):3662-7
8837421
FEMS Microbiol Lett. 2007 Aug;273(1):12-21
17559397
J Bacteriol. 1987 Jan;169(1):283-90
3025174
Trends Biochem Sci. 1991 Apr;16(4):135-40
1877088
Appl Environ Microbiol. 1994 Nov;60(11):4174-7
16349445
Appl Environ Microbiol. 1991 May;57(5):1408-12
16348482
J Biol Chem. 1989 Dec 15;264(35):21122-30
2531744
Int J Food Microbiol. 2000 Apr 10;55(1-3):83-6
10791722
Protein Eng. 2002 Jan;15(1):35-41
11842236
Cell. 1990 Sep 7;62(5):939-44
2203539
Trends Biotechnol. 2004 Jul;22(7):346-53
15245907
Can J Microbiol. 2004 Oct;50(10):845-51
15644899
Appl Environ Microbiol. 1999 Jul;65(7):3033-41
10388700
EMBO J. 1990 Dec;9(12):4027-36
2249663
J Bacteriol. 1992 Nov;174(22):7436-44
1429465
Microbiology (Reading). 1996 Jul;142 ( Pt 7):1685-91
8757733
Proc Natl Acad Sci U S A. 1991 Apr 1;88(7):2874-8
1826368
Microbiology (Reading). 1997 Mar;143(Pt 3):999-1017
9296790
J Biosci Bioeng. 2003;96(2):129-33
16233497
J Biol Chem. 2001 Jan 19;276(3):1814-21
11042186