Effect of acetic acid on ethanol production by Zymomonas mobilis mutant strains through continuous adaptation.
BMC Biotechnol
; 17(1): 63, 2017 08 01.
Article
em En
| MEDLINE
| ID: mdl-28764759
ABSTRACT
BACKGROUND:
Acetic acid is a predominant by-product of lignocellulosic biofuel process, which inhibits microbial biocatalysts. Development of bacterial strains that are tolerant to acetic acid is challenging due to poor understanding of the underlying molecular mechanisms.RESULTS:
In this study, we generated and characterized two acetic acid-tolerant strains of Zymomonas mobilis using N-methyl-N'-nitro-N-nitrosoguanidine (NTG)-acetate adaptive breeding. Two mutants, ZMA-142 and ZMA-167, were obtained, showing a significant growth rate at a concentration of 244 mM sodium acetate, while the growth of Z. mobilis ATCC 31823 were completely inhibited in presence of 195 mM sodium acetate. Our data showed that acetate-tolerance of ZMA-167 was attributed to a co-transcription of nhaA from ZMO0117, whereas the co-transcription was absent in ATCC 31823 and ZMA-142. Moreover, ZMA-142 and ZMA-167 exhibited a converstion rate (practical ethanol yield to theorical ethanol yield) of 90.16% and 86% at 195 mM acetate-pH 5 stress condition, respectively. We showed that acid adaptation of ZMA-142 and ZMA-167 to 146 mM acetate increased ZMA-142 and ZMA-167 resulted in an increase in ethanol yield by 32.21% and 21.16% under 195 mM acetate-pH 5 stress condition, respectively.CONCLUSION:
The results indicate the acetate-adaptive seed culture of acetate-tolerant strains, ZMA-142 and ZMA-167, could enhance the ethanol production during fermentation.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Zymomonas
/
Ácido Acético
/
Etanol
Idioma:
En
Revista:
BMC Biotechnol
Assunto da revista:
BIOTECNOLOGIA
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Taiwan