scholarly journals Influence of fermentation temperature and duration on survival and biocontrol efficacy of Pseudomonas fluorescens Pf153 freeze‐dried cells

2019 ◽  
Vol 128 (1) ◽  
pp. 232-241 ◽  
Author(s):  
I.L. Bisutti ◽  
D. Stephan
Keyword(s):  
Pseudomonas Fluorescens ◽  
Biocontrol Efficacy ◽  
Fermentation Temperature ◽  
Freeze Dried

scholarly journals Accelerated storage testing of freeze-dried Pseudomonas fluorescens BTP1, BB2 and PI9 strains

2012 ◽  
Vol 11 (95) ◽  
pp. 16187-16191 ◽  
Author(s):  
Kanyinda Jean Noeuml l Mputu ◽  
Jacqueline Destain ◽  
Philippe Noki ◽  
Philippe Thonart
Keyword(s):  
Pseudomonas Fluorescens ◽  
Accelerated Storage ◽  
Freeze Dried

Growth of Listeria monocytogenes Restricted by Native Microorganisms and Other Properties of Fresh-Cut Spinach†

1997 ◽  
Vol 60 (8) ◽  
pp. 912-917 ◽  
Author(s):  
ISABELLE BABIC ◽  
A. E. WATADA ◽  
J. G. BUTA
Keyword(s):  
Listeria Monocytogenes ◽  
Pseudomonas Fluorescens ◽  
Inhibitory Effect ◽  
Mixed Cultures ◽  
Bacteriostatic Activity ◽  
Staphylococcus Xylosus ◽  
Freeze Dried ◽  
Fresh Cut ◽  
Spinach Leaves

A study was undertaken to investigate the cause of the bacteriostatic activity of fresh-cut spinach leaves against Listeria monocytogenes. L. monocytogenes was cultivated in pure tryptic soy broth for use as a monoculture, in tryptic soy broth containing 10 mg ml−1 of autoclaved or nonautoclaved freeze-dried spinach powder, and in tryptic soy broth in mixed cultures with various microorganisms isolated from fresh-cut spinach, including Pseudomonas fluorescens biovar I, P. fluorescens biovar III, Staphylococcus xylosus, and an undefined culture of mesophilic aerobic microorganisms (MAMs) isolated from freeze-dried spinach powder. These microorganisms were inoculated at 4.4 log CFU ml−1 and L. monocytogenes was inoculated at 2.4 and 4.4 log CFU ml−1 After 24 h of incubation at 30°C, the populations of the two inoculum levels L. monocytogenes increased to 9.0 and 9.6 log CFU ml−1 in the tryptic soy broth control, to 5.4 and 7.5 in nonautoclaved spinach powder cultures, and to 8.8 and 9.1 log CFU ml−1 in autoclaved spinach powder cultures; In mixed cultures with biovar I of P.fluorescens, L. monocytogenes increased to 7.4 and 8.6 log CFU ml−1; with biovar III to 7.7 and 9.1, with S. xylosus to 7.8 and 9.2, and with the MAMs to 7.1 and 8.0 CFU ml−1 in the low and high listerial inoculum cultures respectively. The LSD(0.05)of the means were 0.5 and 0.6, respectively. The freeze-dried spinach powder had an inhibitory effect on the growth of L. monocytogenes. The inhibitory effect was greatly decreased when the native microorganisms were almost eliminated by heating or irradiation. These results indicate that if L. monocytogenes is present as a contaminant on fresh-cut spinach, its growth probably will be restricted by native microorganisms.

Effect of culture age, protectants, and initial cell concentration on viability of freeze-dried cells ofMetschnikowia pulcherrima

2010 ◽  
Vol 56 (10) ◽  
pp. 809-815 ◽  
Author(s):  
Davide Spadaro ◽  
Annalisa Alessandra Ciavorella ◽  
Jorge Giovanny Lopez-Reyes ◽  
Angelo Garibaldi ◽  
Maria Lodovica Gullino
Keyword(s):  
Freeze Drying ◽  
Cell Concentration ◽  
Yeast Cells ◽  
Initial Cell Concentration ◽  
Commercial Development ◽  
Culture Age ◽  
Biocontrol Efficacy ◽  
High Viability ◽  
Freeze Dried ◽  
Drying Conditions

The effect of freeze-drying using different lyoprotectants at different concentrations on the viability and biocontrol efficacy of Metschnikowia pulcherrima was evaluated. The effects of initial yeast cell concentration and culture age on viability were also considered. Yeast cells grown for 36 h were more resistant to freeze-drying than were 48 h cells. An initial concentration of 108cells·mL–1favoured the highest survival after freeze-drying. When maltose (25%, m/v) was used as protectant, a high cell viability was obtained (64.2%). Cells maintained a high viability after 6 months of storage at 4 °C. The biocontrol efficacy of freeze-dried cells was similar to the activity of fresh cells on ‘Gala’ apples and was slightly lower on ‘Golden Delicious’ apples. After optimizing freeze-drying conditions, the viability of M. pulcherrima cells was similar to that obtained in other studies. The results constitute a first step towards the commercial development of M. pulcherrima as a biocontrol agent.

scholarly journals Carbon-to-Nitrogen Ratio and Carbon Loading of Production Media Influence Freeze-Drying Survival and Biocontrol Efficacy of Cryptococcus nodaensis OH 182.9

2005 ◽  
Vol 95 (6) ◽  
pp. 626-631 ◽  
Author(s):  
Shouan Zhang ◽  
David A. Schisler ◽  
Michael J. Boehm ◽  
Patricia J. Slininger
Keyword(s):  
Biomass Production ◽  
Freeze Drying ◽  
Kernel Weight ◽  
Gibberella Zeae ◽  
Total Biomass ◽  
Head Blight ◽  
Biocontrol Efficacy ◽  
Freeze Dried ◽  
The Difference ◽  
Carbon Loading

Fusarium head blight (FHB), caused by Gibberella zeae, is a devastating disease of wheat worldwide. Cryptococcus nodaensis OH 182.9 is an effective biocontrol agent for this disease. Development of a dried product of OH 182.9 would have potential advantages of ease of handling, favorable economics, and acceptance by end users. Isolate OH 182.9 was grown for 48 and 72 h in semi-defined complete liquid (SDCL) medium with carbon-to-nitrogen (C/N) ratios of 6.5:1, 9:1, 11:1, 15:1, and 30:1, and in SDCL C/N 30:1 media with varied carbon loadings of 7, 14, 21, and 28 g/liter. Total biomass production and cell survival at 15 days after freeze-drying were evaluated. Biomass production of OH 182.9 (CFU per milliliter) was not different for all cultivation time by medium C/N or carbon loading combinations. In general, cells harvested at 48 h survived freeze-drying better than those harvested at 72 h. Survival of freeze-dried cells was greatest for cells grown for 48 h in C/N30:1 medium. Cells produced in C/N 6.5:1 medium generally exhibited the poorest survival. For the C/N 30:1 media, cells from 7 g/liter carbon loading medium harvested after 48 h had the best survival after freeze-drying. The difference in freeze-dried cell populations between superior and inferior treatments was typically 1 to 2 log units at 15 days after freeze-drying. The biomass of OH 182.9 produced in SDCL with varied C/N ratios and in SDCL C/N 30:1 media with differing carbon loadings was tested for biocontrol efficacy against FHB in greenhouse studies. The biomass harvested from SDCL C/N 9:1, 11:1, and 15:1 media after 48 h significantly reduced symptoms of FHB. None of the treatments with cells harvested at 72 h consistently reduced FHB severity (P ≤ 0.05). Cells grown in SDCL C/N 30:1 media with 7 and 14 g/liter carbon loading significantly reduced FHB disease severity. Cells harvested from SDCL C/N 9:1, 11:1, and 30:1 with 14 g/liter carbon increased the 100-kernel weight compared with the disease control. The potential of improving OH 182.9 product quality via management of the nutritional environment of the production medium is demonstrated in this study.

scholarly journals Effect of inoculum preparation and formulation on survival and biocontrol efficacy of Pseudomonas fluorescens F113

1999 ◽  
Vol 86 (1) ◽  
pp. 108-116 ◽  
Author(s):  
Y. Moenne-Loccoz ◽  
M. Naughton ◽  
P. Higgins ◽  
J. Powell ◽  
B. O'Connor ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Biocontrol Efficacy ◽  
Inoculum Preparation
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