The Effect of Potassium Phosphate as a pH Stabilizer on the Production of Gellan by Sphingomonas paucibilis NK-2000

Lee, Nam-Kyu; Jo, Young-Bae; Jin, Il-Hyuck; Son, Chang-Woo; Lee, Jin Woo

doi:10.5352/jls.2009.19.8.1033

Cited by 10 publications

(1 citation statement)

References 26 publications

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“…Therefore, we speculated that relief of H + stress during pH homeostasis by addition of buffering salt in the growth medium may help extend the stability. Previous study has also reported on supplementing buffering salts (such as potassium phosphate) as a pH stabilizer during fermentation (Lee et al, 2009). Adding 0.05 M potassium phosphate buffer into the medium slightly improved the pH 48h stability of DGCC12411 m (Figure 6B).…”

Section: Improvement Of the Lpa Phenotype Stabilitymentioning

confidence: 64%

Stability assessment and improvement of a Lactobacillus plantarum mutant with low post-fermentation acidification characteristics

Chuah

Mao

2020

Journal of Dairy Science

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Intracellular pH homeostasis through the extrusion of a proton by F 0 F 1 -ATPase is one of the key mechanisms used by lactic acid bacteria in response to acid stress, and also influences their post-fermentation acidification. In this study, the genotypic and phenotypic stability of a low post-fermentation acidification (LPA) mutant (designated as DGCC12411 m ) of Lactobacillus plantarum DGCC12411 was assessed. Compared with its mother strain, the pH of DGCC12411 m in De Man, Rogosa, and Sharpe (MRS) broth after 48-h cultivation was 0.35 pH units higher. Incorporation of DGCC12411 m in yogurt stored at ambient temperature (ambient yogurt) showed a reduced post-fermentation acidification during storage at 25°C for 120 d. Wholegenome sequencing analysis showed a SNP mutation (GGT > GAT at positions 505 to 507) in DGCC12411 m , which resulted in the substitution of a highly conserved glycine residue by aspartic acid at the Walker A motif of the F 0 F 1 -ATPase α-subunit. However, degeneration of the LPA phenotype was observed after 5 passages of DGCC12411 m in MRS broth. Analysis of DNA sequencing on both the whole population and the isolates showed that a back mutation occurred at the SNP site (GAT changed back to GGT) over the passaging, and the reversion gradually increased from a ratio of 10.8% at P5 to 60.0% at P10. We also found that the LPA phenotype stability of DGCC12411 m was improved by supplementing 0.1 M potassium phosphate buffer to the growth medium as well as by reducing the inoculation rate of DGCC12411 m to 2% (vol/vol). Such LPA Lactobacillus strains have potential for use as starter cultures in fermented foods with less change in acidity during shelf-life storage.

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Section: Improvement Of the Lpa Phenotype Stabilitymentioning

confidence: 64%