Limits...
Effect of the inactivation of lactate dehydrogenase, ethanol dehydrogenase, and phosphotransacetylase on 2,3-butanediol production in Klebsiella pneumoniae strain.

Guo X, Cao C, Wang Y, Li C, Wu M, Chen Y, Zhang C, Pei H, Xiao D - Biotechnol Biofuels (2014)

Bottom Line: Knock out of ldhA had little influence on the yield of 2,3-BD, whereas knock out of adhE or pta significantly improved the formation of 2,3-BD.Also a double mutant strain with deletion of adhE and ldhA was constructed which resulted in accelerated fermentation and higher 2,3-BD production.The double mutant strain with deletion of adhE and ldhA resulted in accelerated fermentation and higher 2,3-BD production.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education; Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No, 29, 13ST, TEDA, Tianjin 300457, China. peihuadong@hotmail.com.

ABSTRACT

Background: 2,3-Butanediol (2,3-BD) is a high-value chemical usually produced petrochemically but which can also be synthesized by some bacteria. To date, Klebsiella pneumoniae is the most powerful 2,3-BD producer which can utilize a wide range of substrates. However, many by-products are also produced by K. pneumoniae, such as ethanol, lactate, and acetate, which negatively regulate the 2,3-BD yield and increase the costs of downstream separation and purification.

Results: In this study, we constructed K. pneumoniae mutants with lactate dehydrogenase (LDH), acetaldehyde dehydrogenase (ADH), and phosphotransacetylase (PTA) deletion individually by suicide vector conjugation.These mutants showed different behavior of production formation. Knock out of ldhA had little influence on the yield of 2,3-BD, whereas knock out of adhE or pta significantly improved the formation of 2,3-BD. The accumulation of the intermediate of 2,3-BD biosynthesis, acetoin, was decreased in all the mutants. The mutants were then tested in five different carbon sources and increased 2,3-BD was observed. Also a double mutant strain with deletion of adhE and ldhA was constructed which resulted in accelerated fermentation and higher 2,3-BD production. In fed-batch culture this strain achieved more than 100 g/L 2,3-BD from glucose with a relatively high yield of 0.49 g/g.

Conclusion: 2,3-BD production was dramatically improved with the inactivation of adhE and pta. The inactivation of ldhA could advance faster cell growth and shorter fermentation time. The double mutant strain with deletion of adhE and ldhA resulted in accelerated fermentation and higher 2,3-BD production. These results provide new insights for industrial production of 2,3-BD by K. pneumoniae.

No MeSH data available.


Related in: MedlinePlus

Fed-batch fermentation profiles of ΔldhA ΔadhE mutant. DCW, dry cell weight; 2,3-BD, 2,3-Butanediol. The curves were calculated from one measurement of three experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3974439&req=5

Figure 5: Fed-batch fermentation profiles of ΔldhA ΔadhE mutant. DCW, dry cell weight; 2,3-BD, 2,3-Butanediol. The curves were calculated from one measurement of three experiments.

Mentions: Fed-batch culture could enhance 2,3-BD production and reduce the cost of production by taking full advantage of the substrate. Thus, fed-batch fermentations were conducted in a 5-L bioreactor. As shown in Figure 5, a fed-batch culture was carried out by feeding glucose solution. In order to maintain optimum levels of glucose, about 750 mL of 600 g/L glucose was added to the bioreactor throughout the fermentation. After 52 h, the fed-batch fermentation of the ΔadhE ΔldhA strain produced about 116 g/L of 2,3-BD, whereas the time courses of the other metabolites had the same tendency with the batch culture (Figure 5).


Effect of the inactivation of lactate dehydrogenase, ethanol dehydrogenase, and phosphotransacetylase on 2,3-butanediol production in Klebsiella pneumoniae strain.

Guo X, Cao C, Wang Y, Li C, Wu M, Chen Y, Zhang C, Pei H, Xiao D - Biotechnol Biofuels (2014)

Fed-batch fermentation profiles of ΔldhA ΔadhE mutant. DCW, dry cell weight; 2,3-BD, 2,3-Butanediol. The curves were calculated from one measurement of three experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3974439&req=5

Figure 5: Fed-batch fermentation profiles of ΔldhA ΔadhE mutant. DCW, dry cell weight; 2,3-BD, 2,3-Butanediol. The curves were calculated from one measurement of three experiments.
Mentions: Fed-batch culture could enhance 2,3-BD production and reduce the cost of production by taking full advantage of the substrate. Thus, fed-batch fermentations were conducted in a 5-L bioreactor. As shown in Figure 5, a fed-batch culture was carried out by feeding glucose solution. In order to maintain optimum levels of glucose, about 750 mL of 600 g/L glucose was added to the bioreactor throughout the fermentation. After 52 h, the fed-batch fermentation of the ΔadhE ΔldhA strain produced about 116 g/L of 2,3-BD, whereas the time courses of the other metabolites had the same tendency with the batch culture (Figure 5).

Bottom Line: Knock out of ldhA had little influence on the yield of 2,3-BD, whereas knock out of adhE or pta significantly improved the formation of 2,3-BD.Also a double mutant strain with deletion of adhE and ldhA was constructed which resulted in accelerated fermentation and higher 2,3-BD production.The double mutant strain with deletion of adhE and ldhA resulted in accelerated fermentation and higher 2,3-BD production.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education; Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, Box 08, No, 29, 13ST, TEDA, Tianjin 300457, China. peihuadong@hotmail.com.

ABSTRACT

Background: 2,3-Butanediol (2,3-BD) is a high-value chemical usually produced petrochemically but which can also be synthesized by some bacteria. To date, Klebsiella pneumoniae is the most powerful 2,3-BD producer which can utilize a wide range of substrates. However, many by-products are also produced by K. pneumoniae, such as ethanol, lactate, and acetate, which negatively regulate the 2,3-BD yield and increase the costs of downstream separation and purification.

Results: In this study, we constructed K. pneumoniae mutants with lactate dehydrogenase (LDH), acetaldehyde dehydrogenase (ADH), and phosphotransacetylase (PTA) deletion individually by suicide vector conjugation.These mutants showed different behavior of production formation. Knock out of ldhA had little influence on the yield of 2,3-BD, whereas knock out of adhE or pta significantly improved the formation of 2,3-BD. The accumulation of the intermediate of 2,3-BD biosynthesis, acetoin, was decreased in all the mutants. The mutants were then tested in five different carbon sources and increased 2,3-BD was observed. Also a double mutant strain with deletion of adhE and ldhA was constructed which resulted in accelerated fermentation and higher 2,3-BD production. In fed-batch culture this strain achieved more than 100 g/L 2,3-BD from glucose with a relatively high yield of 0.49 g/g.

Conclusion: 2,3-BD production was dramatically improved with the inactivation of adhE and pta. The inactivation of ldhA could advance faster cell growth and shorter fermentation time. The double mutant strain with deletion of adhE and ldhA resulted in accelerated fermentation and higher 2,3-BD production. These results provide new insights for industrial production of 2,3-BD by K. pneumoniae.

No MeSH data available.


Related in: MedlinePlus