Bacillus subtilis natto: a non-toxic source of poly-γ-glutamic acid that could be used as a cryoprotectant for probiotic bacteria

Aditya R Bhat, Victor U Irorere, Terry Bartlett, David Hill, Gopal Kedia, Mark R Morris, Dimitris Charalampopoulos, Iza Radecka

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

It is common practice to freeze dry probiotic bacteria to improve their shelf life. However, the freeze drying process itself can be detrimental to their viability. The viability of probiotics could be maintained if they are administered within a microbially produced biodegradable polymer - poly-γ-glutamic acid (γ-PGA) - matrix. Although the antifreeze activity of γ-PGA is well known, it has not been used for maintaining the viability of probiotic bacteria during freeze drying. The aim of this study was to test the effect of γ-PGA (produced by B. subtilis natto ATCC 15245) on the viability of probiotic bacteria during freeze drying and to test the toxigenic potential of B. subtilis natto. 10% γ-PGA was found to protect Lactobacillus paracasei significantly better than 10% sucrose, whereas it showed comparable cryoprotectant activity to sucrose when it was used to protect Bifidobacterium breve and Bifidobacterium longum. Although γ-PGA is known to be non-toxic, it is crucial to ascertain the toxigenic potential of its source, B. subtilis natto. Presence of six genes that are known to encode for toxins were investigated: three component hemolysin (hbl D/A), three component non-haemolytic enterotoxin (nheB), B. cereus enterotoxin T (bceT), enterotoxin FM (entFM), sphingomyelinase (sph) and phosphatidylcholine-specific phospholipase (piplc). From our investigations, none of these six genes were present in B. subtilis natto. Moreover, haemolytic and lecithinase activities were found to be absent. Our work contributes a biodegradable polymer from a non-toxic source for the cryoprotection of probiotic bacteria, thus improving their survival during the manufacturing process.
LanguageEnglish
Pages36
Number of pages1
JournalAMB Express
Volume3
DOIs
Publication statusPublished - 2013

Fingerprint

polyglutamic acid
natto
cryoprotectants
Bacillus subtilis
probiotics
enterotoxins
freeze drying
viability
bacteria
biodegradability
polymers
Bifidobacterium breve
sucrose
Lactobacillus paracasei
Cereus
Bifidobacterium longum
hemolysins
phosphatidylcholines
shelf life
manufacturing

Cite this

Bhat, Aditya R ; Irorere, Victor U ; Bartlett, Terry ; Hill, David ; Kedia, Gopal ; Morris, Mark R ; Charalampopoulos, Dimitris ; Radecka, Iza. / Bacillus subtilis natto: a non-toxic source of poly-γ-glutamic acid that could be used as a cryoprotectant for probiotic bacteria. In: AMB Express. 2013 ; Vol. 3. pp. 36.
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abstract = "It is common practice to freeze dry probiotic bacteria to improve their shelf life. However, the freeze drying process itself can be detrimental to their viability. The viability of probiotics could be maintained if they are administered within a microbially produced biodegradable polymer - poly-γ-glutamic acid (γ-PGA) - matrix. Although the antifreeze activity of γ-PGA is well known, it has not been used for maintaining the viability of probiotic bacteria during freeze drying. The aim of this study was to test the effect of γ-PGA (produced by B. subtilis natto ATCC 15245) on the viability of probiotic bacteria during freeze drying and to test the toxigenic potential of B. subtilis natto. 10{\%} γ-PGA was found to protect Lactobacillus paracasei significantly better than 10{\%} sucrose, whereas it showed comparable cryoprotectant activity to sucrose when it was used to protect Bifidobacterium breve and Bifidobacterium longum. Although γ-PGA is known to be non-toxic, it is crucial to ascertain the toxigenic potential of its source, B. subtilis natto. Presence of six genes that are known to encode for toxins were investigated: three component hemolysin (hbl D/A), three component non-haemolytic enterotoxin (nheB), B. cereus enterotoxin T (bceT), enterotoxin FM (entFM), sphingomyelinase (sph) and phosphatidylcholine-specific phospholipase (piplc). From our investigations, none of these six genes were present in B. subtilis natto. Moreover, haemolytic and lecithinase activities were found to be absent. Our work contributes a biodegradable polymer from a non-toxic source for the cryoprotection of probiotic bacteria, thus improving their survival during the manufacturing process.",
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Bhat, AR, Irorere, VU, Bartlett, T, Hill, D, Kedia, G, Morris, MR, Charalampopoulos, D & Radecka, I 2013, 'Bacillus subtilis natto: a non-toxic source of poly-γ-glutamic acid that could be used as a cryoprotectant for probiotic bacteria', AMB Express, vol. 3, pp. 36. https://doi.org/10.1186/2191-0855-3-36

Bacillus subtilis natto: a non-toxic source of poly-γ-glutamic acid that could be used as a cryoprotectant for probiotic bacteria. / Bhat, Aditya R; Irorere, Victor U; Bartlett, Terry; Hill, David; Kedia, Gopal; Morris, Mark R; Charalampopoulos, Dimitris; Radecka, Iza.

In: AMB Express, Vol. 3, 2013, p. 36.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Bacillus subtilis natto: a non-toxic source of poly-γ-glutamic acid that could be used as a cryoprotectant for probiotic bacteria

AU - Bhat, Aditya R

AU - Irorere, Victor U

AU - Bartlett, Terry

AU - Hill, David

AU - Kedia, Gopal

AU - Morris, Mark R

AU - Charalampopoulos, Dimitris

AU - Radecka, Iza

PY - 2013

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