Add like
Add dislike
Add to saved papers

Homo-ethanol production from glycerol and gluconate using recombinant Klebsiella oxytoca strains.

Gluconic acid, an oxidized cellulose degradation product, could be produced from cellulosic biomass. Glycerol is a cheap and renewable resource for fuels and chemicals production and is available as a byproduct of biodiesel production. Gluconate is a more oxidized substrate than glucose, whereas glycerol is a more reduced substrate than glucose. While the production of homo-ethanol from glucose can be achieved, the conversion of gluconate to ethanol is accompanied by the production of oxidized byproduct such as acetate, and reduced byproducts such as 1,3-propanediol are produced along ethanol when glycerol is used as the carbon source. When gluconate and glycerol were used as the sole carbon source by Klebsiella oxytoca BW 21, ethanol yield was about 62%-64%. Co-utilization of both gluconate and glycerol in batch fermentation increased the yield of ethanol to about 78.7% and decreased by-product accumulation (such as acetate and 1,3-propanediol) substantially. Decreasing by-product formation by deleting the pta, frd, ldh, pflA, and pduC genes in strain BW21 increased the ethanol yield to 89.3% in the batch fermentation of a glycerol-gluconate mixture. These deletions produced the strain K. oxytoca WT26. However, the utilization rate of glycerol was significantly slower than that of gluconate in batch fermentation. Additionally, substantial amounts of glycerol remain unutilized after gluconate was depleted in batch fermentation. Continuous fed-batch fermentation was used to solve the utilization rate mismatch problem for gluconate and glycerol. An ethanol yield of 97.2% was achieved in continuous fed-batch fermentation of these two substrates, and glycerol was completely used at the end of the fermentation. IMPORTANCE: Gluconate is a biomass-derived degradation product, and glycerol can be obtained as a biodiesel byproduct. Compared to glucose, using them as the sole substrate is accompanied by the production of byproducts. Our study shows that through pathway engineering and adoption of a fed-batch culture system, high yield homo-ethanol production that usually can be achieved by using glucose as the substrate is achievable using gluconate and glycerol as co-substrates. The same strategy is expected to be able to achieve homo-fermentative production of other product such as lactate and 2,3- Butanediol which can be typically achieved using glucose as the substrate, using inexpensive biodiesel derived glycerol and biomass-derived gluconate as the co-substrates.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app