Effect of the pH of growth on the survival of Lactobacillus delbrueckii subsp. bulgaricus to stress conditions during spray-drying

Silva, Joana; Carvalho, Ana Sofia; Ferreira, Rita; Vitorino, Rui; Amado, Francisco; Domingues, Pedro; Teixeira, Paula; Gibbs, Paul

doi:10.1111/j.1365-2672.2004.02516.x

Cited by 79 publications

(58 citation statements)

References 37 publications

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“…Several reports have suggested that improved stress tolerance can be achieved if cells are mildly stressed during growth [29,36], and correlations between membrane lipid compositions of different Lactobacillus spp. and their freeze tolerance (cryotolerance) have been demonstrated [1,35].…”

Section: Introductionmentioning

confidence: 99%

Impact of fermentation pH and temperature on freeze-drying survival and membrane lipid composition of Lactobacillus coryniformis Si3

Schoug¹,

Fischer²,

Heipieper³

et al. 2007

J Ind Microbiol Biotechnol

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During the industrial stabilization process, lactic acid bacteria are subjected to several stressful conditions. Tolerance to dehydration differs among lactic acid bacteria and the determining factors remain largely unknown. Lactobacillus coryniformis Si3 prevents spoilage by mold due to production of acids and specific antifungal compounds. This strain could be added as a biopreservative in feed systems, e.g. silage. We studied the survival of Lb. coryniformis Si3 after freeze-drying in a 10% skim milk and 5% sucrose formulation following different fermentation pH values and temperatures. Initially, a response surface methodology was employed to optimize final cell density and growth rate. At optimal pH and temperature (pH 5.5 and 34 degrees C), the freeze-drying survival of Lb. coryniformis Si3 was 67% (+/-6%). The influence of temperature or pH stress in late logarithmic phase was dependent upon the nature of the stress applied. Heat stress (42 degrees C) did not influence freeze-drying survival, whereas mild cold- (26 degrees C), base- (pH 6.5), and acid- (pH 4.5) stress significantly reduced survival. Freeze-drying survival rates varied fourfold, with the lowest survival following mild cold stress (26 degrees C) prior to freeze-drying and the highest survival after optimal growth or after mild heat (42 degrees C) stress. Levels of different membrane fatty acids were analyzed to determine the adaptive response in this strain. Fatty acids changed with altered fermentation conditions and the degree of membrane lipid saturation decreased when the cells were subjected to stress. This study shows the importance of selecting appropriate fermentation conditions to maximize freeze-drying viability of Lb. coryniformis as well as the effects of various unfavorable conditions during growth on freeze-drying survival.

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Section: Introductionmentioning

confidence: 99%

Impact of fermentation pH and temperature on freeze-drying survival and membrane lipid composition of Lactobacillus coryniformis Si3

Schoug¹,

Fischer²,

Heipieper³

et al. 2007

J Ind Microbiol Biotechnol

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“…The pH and temperature of the control culture (MRS broth) were 6.5 and 37 o C, respectively, according to manufacturer's recommendation and as described previously (Boot et al, 1993;Silva et al, 2005;Smit et al, 2001). …”

Section: Stress Conditionsmentioning

confidence: 99%

Effect of Environmental Stresses on S-Layer Production in Lactobacillus acidophilus ATCC 4356

Khaleghi¹,

Kermanshahi²

2012

Advances in Applied Biotechnology

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“…Previously, we found that up to 16-to 18-fold better survival of L. paracasei NFBC 338 spray-dried in RSM (20%, wt/vol) occurred at outlet temperature 95 to 105°C as a result of salt or heat adaptation (6), while another study demonstrated that growth at an uncontrolled pH increased the survival of Lactobacillus delbrueckii subsp. bulgaricus after spray-drying up to 10-fold, which was linked to overexpression of GroEL (20). A comparison of these data indicated that although GroESL plays a major role in the survival of L. paracasei NFBC 338 during exposure to stress, it is part of a wider arsenal of mechanisms (5).…”

mentioning

confidence: 99%

Enhanced Survival of GroESL-Overproducing Lactobacillus paracasei NFBC 338 under Stressful Conditions Induced by Drying

Corcoran

Ross

Fitzgerald

et al. 2006

Appl Environ Microbiol

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GroESL-overproducing Lactobacillus paracasei NFBC 338 was dried, and its viability was compared with that of controls. Spray-and freeze-dried cultures overproducing GroESL exhibited ϳ10-fold and 2-fold better survival, respectively, demonstrating the importance of GroESL in stress tolerance, which can be exploited to enhance the technological performance of sensitive probiotic cultures.The health benefits associated with consumption of probiotic bacteria have been well characterized (13,18). From a processing perspective, these microorganisms must be suitable for large-scale industrial production, so that up to 10 7 CFU g Ϫ1 are present in a food product at the end of its shelf-life. Spraydrying is an effective method for producing stable powders at low operating costs; however, the survival rates of lactic acid bacteria are often low (12), and the loss of viability is caused principally by cell membrane damage (1). Freeze-drying exposes cells to attenuating effects of freezing and rehydration. In addition, the secondary structures of RNA and DNA stabilize, resulting in reduced efficacy of DNA replication, transcription, and translation (27). Lactobacillus paracasei NFBC 338 is a suitable probiotic candidate for spray-drying (8), and heat or salt adaptation increased its tolerance to spray drying (6). As GroESL was upregulated following heat stress of L. paracasei NFBC 338, we homologously overexpressed the GroESL operon in L. paracasei NFBC 338, thereby conferring protection during heat, salt, and butanol stresses (5). The chaperone protein GroESL refolds denatured proteins during heat stress (17). The functions of the chaperone do not appear to be limited to heat stress but involve a wider role in cellular processes, such as growth (7), mRNA stability (9), and cytoplasmic protein folding (10). The studies described in this paper built on these findings and demonstrated that L. paracasei NFBC 338 overproducing GroESL exhibited enhanced survival during drying, thus demonstrating a novel use for an overproduced chaperone protein.In order to evaluate the significance of overexpression of GroESL on the technological performance of a probiotic strain during drying, L. paracasei NFBC 338 containing either pGRO2 (an overproducer of GroESL) or pMSP3535 (control) was grown to the late exponential phase as previously described (5), centrifuged, suspended in reconstituted skim milk (RSM) (20%, wt/vol) to a final density of 2.0 ϫ 10 9 to 2.5 ϫ 10 9 CFU g Ϫ1 , and spray-dried. A laboratory-scale spray-dryer (model B191 Buchi mini spray-dryer; Flawil, Switzerland) was used to process samples at a constant air inlet temperature of 180°C and an outlet temperature of 95 to 100°C, and the percentage of surviving bacteria was determined as described previously (8). Following spray-drying, cultures overproducing GroESL exhibited approximately 10-fold better survival (P Ͻ 0.05) than controls; this treatment resulted in powders that contained 8.03 ϫ 10 7 CFU g Ϫ1 and exhibited 5.15% survival, while cultures of L. paracasei NFBC 338 ...

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Effect of the pH of growth on the survival of Lactobacillus delbrueckii subsp. bulgaricus to stress conditions during spray-drying

Cited by 79 publications

References 37 publications

Impact of fermentation pH and temperature on freeze-drying survival and membrane lipid composition of Lactobacillus coryniformis Si3

Impact of fermentation pH and temperature on freeze-drying survival and membrane lipid composition of Lactobacillus coryniformis Si3

Effect of Environmental Stresses on S-Layer Production in Lactobacillus acidophilus ATCC 4356

Enhanced Survival of GroESL-Overproducing Lactobacillus paracasei NFBC 338 under Stressful Conditions Induced by Drying

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