PDF Publication Title:
Text from PDF Page: 008
Materials 2019, 12, 350 8 of 22 alcohol and guerbet alcohol this extractant can increase butanol productivity 2.5-fold in comparison to conventional fermentation processes. The identification of further non-toxic compounds or mixtures of compounds could help improve liquid–liquid extraction of butanol from fermentation broth. Fermentation integrated with gas stripping is an attractive technology for larger-scale biobutanol synthesis. In a novel two-stage gas stripping process integrated with acetone-butanol-ethanol fermentation, more ABE was produced with higher butanol productivity (0.34 g/L · h). This was a result of reduced butanol inhibition caused by butanol recovery. First-stage gas stripping produced a condensate containing 155.6 g/L butanol, and after phase separation an organic phase was obtained containing 610.8 g/L butanol. Second-stage pervaporation produced a condensate with 441.7 g/L butanol, which after mixing with the organic phase from gas stripping gave 521.3 g/L butanol [137]. Strain Improvement The mechanism underlying the response of C. acetobutylicum to butanol stress is still poorly understood. According to recent studies by Wang et al. [138], glycolysis by C. acetobutylicum may be inhibited under butanol stress, while the TCA cycle is be promoted. The key factors determining the metabolic response of Clostridium spp. to butanol stress are thought to be changes in the lipid and fatty acid compositions of bacterial cells, to the intracellular metabolism and to the osmoregulator concentrations. The same authors suggest that C. acetobutylicum cells change their levels of long acyl chain saturated fatty acids and branched-chain amino acids to adjust their fluidity and maintain the integrity of their cell membranes under butanol stress. Increased levels of some amino acids (threonine, glycine, alanine, phenylalanine, tyrosine, tryptophan, aspartate and glutamate) could also be responsible for increasing the tolerance of C. acetobutylicum to butanol. Increased levels of glycerol have likewise been correlated with osmoregulation and the regulating redox balance. These results point towards the possibility of synthesizing butanologenic strains with higher butanol tolerance. Liu et al. [139] developed a novel approach known as 1-butanoleglycerol storage to enhance butanol tolerance and prevent productive degeneration in C. acetobutylicum during long-term preservation. After 12 months under optimal storage conditions at 37 ◦C, the cell survival rate in a solution containing 16 g/L butanol mixed with 200 g/L glycerol was 80% and the bacterial cells showed enhanced butanol tolerance of 32 g/L. This was around 2-fold higher than for the wild-type strain. Moreover, the butanol yield was slightly higher compared to the control. These results show that the conditions under which cultures are preserved are very important for enhancing butanol tolerance and preventing loss of productivity. The use of metabolic engineering has the potential to increase butanol production [55]. Strategies to prevent the destruction of bacterial cells by butanol synthesized via fermentation processes include the genetic engineering of high-butanol producing strains [120]. Lin et al. [140] executed random mutagenesis to metamorphose the deoxyribonucleic acid (DNA) sequence of genes responsible for butanol formation. The mutant strain C. acetobutylicum ATCC 824 was developed by serial enrichment of diluted n-butanol. The strain was found to have significantly higher butanol tolerance (121%) than the native strain. Another novel mutant was developed from C. acetobutylicum, which was treated with a combination of N-methyl-N’-nitro-N-nitrosoguanidine (MMNG), ethyl methane sulphonate and UV exposure [141]. This strain showed greater potency (20%) in molasses and gave higher butanol yields in comparison to the parent strain. Systems-level metabolic engineering of clostridia may lead to the discovery of entirely new biosynthetic pathways for butanol, and to the development of new strains which could overcome the current limitations of butanol fermentation by clostridia (Figure 2) [84,142–148].PDF Image | Butanol Synthesis Routes for Biofuel Production
PDF Search Title:
Butanol Synthesis Routes for Biofuel ProductionOriginal File Name Searched:
materials-12-00350.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |