Limited oxygen conditions as an approach to scale-up and improve d and l-lactic acid production in mineral media and avocado seed hydrolysates with metabolically engineered Escherichia coli

Author(s):  
Estefanía Sierra-Ibarra ◽  
Laura J. Leal-Reyes ◽  
Gerardo Huerta-Beristain ◽  
Ana L. Hernández-Orihuela ◽  
Guillermo Gosset ◽  
...  
2011 ◽  
Vol 74 (1) ◽  
pp. 94-100 ◽  
Author(s):  
A. LONDERO ◽  
R. QUINTA ◽  
A. G. ABRAHAM ◽  
R. SERENO ◽  
G. DE ANTONI ◽  
...  

We investigated the chemical and microbiological compositions of three types of whey to be used for kefir fermentation as well as the inhibitory capacity of their subsequent fermentation products against 100 Salmonella sp. and 100 Escherichia coli pathogenic isolates. All the wheys after fermentation with 10% (wt/vol) kefir grains showed inhibition against all 200 isolates. The content of lactic acid bacteria in fermented whey ranged from 1.04 × 107 to 1.17 × 107 CFU/ml and the level of yeasts from 2.05 × 106 to 4.23 × 106 CFU/ml. The main changes in the chemical composition during fermentation were a decrease in lactose content by 41 to 48% along with a corresponding lactic acid production to a final level of 0.84 to 1.20% of the total reaction products. The MIC was a 30% dilution of the fermentation products for most of the isolates, while the MBC varied between 40 and 70%, depending on the isolate. The pathogenic isolates Salmonella enterica serovar Enteritidis 2713 and E. coli 2710 in the fermented whey lost their viability after 2 to 7 h of incubation. When pathogens were deliberately inoculated into whey before fermentation, the CFU were reduced by 2 log cycles for E. coli and 4 log cycles for Salmonella sp. after 24 h of incubation. The inhibition was mainly related to lactic acid production. This work demonstrated the possibility of using kefir grains to ferment an industrial by-product in order to obtain a natural acidic preparation with strong bacterial inhibitory properties that also contains potentially probiotic microorganisms.


2012 ◽  
Vol 34 (11) ◽  
pp. 2069-2075 ◽  
Author(s):  
Yongze Wang ◽  
Tian Tian ◽  
Jinfang Zhao ◽  
Jinhua Wang ◽  
Tao Yan ◽  
...  

2013 ◽  
Vol 641-642 ◽  
pp. 721-724
Author(s):  
Zhao Min Zheng ◽  
Tian Tian ◽  
Jin Hua Wang ◽  
Yong Ze Wang ◽  
Sheng De Zhou

WD100, knocked out adhE of Escherichia coli SZ470 and inserted ldhA into Escherichia coli WD01, was genetically engineered to utilize xylose. D-lactate production was investigated for shake flask cultures with xylose. In 64h WD100 produce 10.1g/L D-lactate in the shaking flask And it consumed 25g/L xylose during the ending of fermentation.This volumetric productivity with xylose is 0.14 g·L-1·h-1.Because of pyruvate decarboxylase (poxB) expressed in flask fermention,acetate production was up to 4.7g/L.Succinate,formate,ethanol was also produced as a minor product during fermentation.


2022 ◽  
Vol 177 ◽  
pp. 114519
Author(s):  
Júnia Alves-Ferreira ◽  
Florbela Carvalheiro ◽  
Luís C. Duarte ◽  
Ana R.P. Ferreira ◽  
Alfredo Martinez ◽  
...  

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