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NON TECHNICAL SUMMARY:
Many small molecule fermentation products from biomass e.g., butanol, acetone, ethanol, acetic acid, propionic acid etc. are valuable sources of chemicals as well as fuels. Their efficient recovery from their dilute solutions in a fermentation broth will be achieved in this project by their highly selective transport over water through special separation membranes. Such a membrane separation technology will be developed in this project. The efficient recovery of small bioproducts from the fermentation broths will be demonstrated here by combining the membrane separation device with a fermentor.
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| OBJECTIVES:
Develop a novel composite membrane system from surface modified porous hydrophobic polypropylene (PP) hollow fibers and an appropriate liquid membrane in the macropores of the PP hollow fibers and determine their separation performances from model solutions of individual bioproducts, such as butanol, ethanol, acetic acid, propionic acid and butyric acid under the influence of permeate side vacuum. Study a batch fermentation system externally coupled with the novel membrane device and total broth recycle for the production and recovery of acetone, butanol and ethanol (ABE) from Clostridium acetobutylicum. Study batch fermentation also with total broth recycle for the production and recovery of propionic acid.
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| APPROACH:
An ultrathin polymeric coating will be developed on the outside surface of porous hydrophobic polypropylene (PP) hollow fibers by plasmapolymerization. This coating will be highly permeable to smaller volatile bioproducts, such as, acetone, butanol, ethanol, acetic acid and propionic acid whose transport will be highly facilitated vis-a-vis water by the nonvolatile organic solvents/complexing agents immobilized in the macropores of PP fibers. The removal of individual volatile bioproducts from a synthetic medium by such a composite liquid membrane subjected to a vacuum in the hollow fiber bore side will be investigated for their individual fluxes and selectivity with respect to water. This membrane technology will then be coupled externally with a fermentor where either ABE production using Clostridium acetobutylicum or propionic acid production via Propionibacterium acidipropionici will be taking place. The performance of each fermentation system and the efficiency of
membrane-based product recovery will be studied.
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CRIS NUMBER: 0196731
SUBFILE: CRIS
PROJECT NUMBER: NJR-2003-01101
SPONSOR AGENCY: CSREES
PROJECT TYPE: NRI COMPETITIVE GRANT
PROJECT STATUS: TERMINATED
MULTI-STATE PROJECT NUMBER: (N/A)
START DATE: Sep 1, 2003
TERMINATION DATE: Aug 31, 2006
GRANT PROGRAM: NON-FOOD CHARACTERIZATION/PROCESS/PRODUCT
GRANT PROGRAM AREA: Value Added Products
CLASSIFICATION
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| 511 | 7410 | 2000 | 2.1 | 60% |
| 511 | 7410 | 2020 | 2.1 | 40% |
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CLASSIFICATION HEADINGS
KA511 - New and Improved Non-Food Products and Processes
S7410 - General technology
F2020 - Engineering
F2000 - Chemistry
G2.1 - Expand Domestic Market Opportunities
RESEARCH EFFORT CATEGORIES
| BASIC |
70% |
| APPLIED |
30% |
| DEVELOPMENTAL |
(N/A)% |
KEYWORDS: volatile substances; new technology; engineering; fermentation; membranes; flow; selectivity; new products; chemical engineering; fibers; liquids; systems development; butanol; ethanol; acetic acid; propionic acid; butyric acid; recycling; acetone; clostridium acetobutylicum; coatings; polymerization; biomass
PROGRESS: Sep 1, 2003 TO Aug 31, 2006
Pervaporation is an energy- efficient alternative to distillation for removing volatile organic compounds from water especially solvents from their dilute solutions in a fermentation broth. Polymeric, ceramic and liquid membranes have been used in pervaporation for removing such solvents; however, polymeric and ceramic membranes have poor solvent selectivity compared to liquid membranes even though they achieve reasonable solvent mass fluxes. Liquid membranes have stability problems due to various losses. The loss of liquid membrane (LM) to the feed leads to toxicity for the organisms in a broth. A new liquid membrane based pervaporation technique has been developed to achieve high selectivity, ensure stability and prevent contamination of the fermentation broth. Trioctylamine (TOA) was immobilized in the pores of a hydrophobic hollow fiber substrate having a nanoporous hydrophobic coating on the broth side and studied for pervaporation-based removal of solvents
(acetone, ethanol, and butanol) from their dilute aqueous solutions. The LM of TOA in the coated hollow fibers demonstrated high selectivity and reasonable mass fluxes of solvents in pervaporation. The selectivities and fluxes were considerably increased when the feed temperature was raised. The selectivities of butanol, acetone, and ethanol achieved were 275, 220, and 80 respectively with 11.0, 5.0, and 1.2 g/m2-hr for the mass fluxes of butanol, acetone and ethanol respectively at a temperature of 54 Celsius for a feed solution containing butanol 1.5 %, acetone 0.8 % and ethanol 0.5 %. In similar experiments using porous hydrophobic polymeric hollow fibers without any coating, selectivities were similar but the fluxes were higher by 1.3 to 1.9 times. However, the noncoated fibers contaminated the aqueous feed and the lifetime of the LM was considerably reduced. The mass fluxes were substantially increased (by 3.5 times) with the same selectivity for solvents when an ultrathin liquid
membrane was used in the coated fibers. The TOA-based LM present throughout the pores of the coated substrate demonstrated excellent stability over more than 300 hours of experiment (it is still running) without any reimmobilization and essentially prevented liquid membrane loss to the feed solution and the latter's contamination by the liquid membrane. Contamination of the feed solution by TOA was studied. The concentration of TOA in the aqueous feed after 4 hours and a 35 Celsius experiment was only 0.3 ppm, which is quite low. The filtered fermentation broth produced from C. acetobutylicum ATCC 824 was also studied for pervaporation performance with the thin liquid membrane. The selectivities at 54 Celsius of butanol, acetone and ethanol were 197, 111, and 54 respectively; the solvent fluxes were 31, 9 and 4 g/m2-hr for butanol, acetone and ethanol respectively. This TOA-based stable liquid membrane in the coated fibers demonstrated considerable success in selectively removing
solvents from their dilute solutions in a fermentation broth. However, it would be useful to increase the species fluxes further and study the stability of the membrane over a much longer period of time.
IMPACT: 2003-09-01 TO 2006-08-31
Solvents and chemicals (such as butanol, acetone, ethanol, etc.) produced by fermentation are present in low concentrations in the fermentation broth. Recovering them by distillation is costly due to the significant energy requirement. The energy required for recovering these solvents by pervaporation is much less. However, the pervaporation membrane must be highly selective and have high flux for the solvents/chemicals produced by fermentation. We have developed such a membrane using a nonvolatile liquid. This liquid membrane system is stable, does not contaminate the broth, and has a high selectivity and reasonable flux for the products of interest. This technique is a step toward an economic recovery of fermentation-generated solvents and chemicals.
PUBLICATION INFORMATION: 2003-09-01 TO 2006-08-31
A. Thongsukmak and K.K. Sirkar, Pervaporation Membranes Highly Selective for Solvents Present in Fermentation Broths,Submitted for publication (2006).
PROJECT CONTACT INFORMATION
| NAME: |
Dr. Sirkar, K. K. |
| PHONE: |
973-596-8447 |
| FAX: |
976-642-4854 |
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