高分子概論
Membrane contactor
(pertraction)
班級:化材三乙
姓名:張銘浩
學號:49940086
一. 原理說明
The proposed research project, namely the study on separation by free, facilitated
and/or synergetic pertraction (extraction through liquid membranes) of some valuable
biosynthetic products, joins the top of the worldwide researches on separation of
biosynthetic compounds with important applications in medicine, food and cosmetics,
researches that are connected to the current context of “the white biotechnology”.
Compared to the chemical methods, the biosynthesis represents a very advantageous
alternative for production of many compounds with biological activity, because of the
reduction of the overall process stages number and of the advanced utilization of the
lowcost raw materials.
However, the undesirable particularity of industrial biotechnologies is the complexity
of the separation from fermentation broths of the obtained products, especially due to
their high dilution in broth, chemical and thermal lability and to the presence of
secondary products. Therefore, the purification of biosynthetic compounds requires a
laborious succession of separation stages with high material and energy consumption,
the contribution of these stages to the overall cost being of 20 - 60%, or even more.
For this reason, most of the research and development directions on separation
techniques are focused on the biosynthetic compounds. In this context, among the
wideworld studies on new separation methods for the biosynthetic products two major
directions can be pointed out: reactive extraction and extraction through liquid
membranes, or pertraction.
Extraction and transport through liquid membranes, also called pertraction or
permeation, represents the development of reactive extraction technique. Pertraction
consists in the transfer of a solute between two aqueous phases of different pH or
other chemical properties value, phases that are separated by a
solvent layer of various sizes.
By comparing the extraction using liquid membranes with conventional liquid-liquid
extraction, the advantages of the pertraction are as follows: the quantity of solvent
used is small, because of its continuous regeneration; the loss of solvent during
extraction and transport process is reduced; as long as the pH gradient between the
two aqueous phases is maintained, there is the possibility of solute transport against
its concentration gradient; higher diffusion coefficient of permeates in liquid
membranes compared to polymeric membranes; energy consumption is very low.
The pertraction efficiency could be significantly enhanced by adding one or more
carriers in liquid.
membrane, such as organophosphoric compounds, long chain amines or crown-ethers,
the separation process being called facilitated pertraction (for one carrier) or
synergetic pertraction (for mixture of carriers or solvents inducing the synergetic
effect).
Because the use of biotechnology and the optimization of the high cost
biotechnological stages represent one of the priorities, the proposed project
contributes to the development of the fundamental and
applicative researches in the bioengineering and biotechnology domain in our country,
all the more as the activity and the previous results of our team in this field are
appreciated in the scientific media.
New valences of the multidisciplinary research are promoted by means of this project,
in the purpose of increasing the economically efficiency of the biotechnologies for
production of antibiotics, carboxylic
acids, amino acids and vitamins with pharmaceutical, food and cosmetic utilizations.
Therefore, the original
objectives of the proposed project and the novelty and scientifically interest of the
corresponding potential
results are as follows (the potential results could be considered as intermediate
milestones):
1. individual and selective separation of carboxylic acids obtained by succinic
fermentation with Actinobacillus succinogenes (succinic, formic and acetic acids) by
facilitated pertraction;
2. individual and selective separation of carboxylic
acids obtained by propionic fermentation with Torulopsis glabrata (propionic,
pyruvic acids, and acetic acid – the last acid included in the above objective) by
facilitated pertraction;
3. separation by reactive extraction and facilitated
pertraction of mupirocin (pseudomonic acid, antibiotic produced by Pseudomona
fluorescens);
4. separation of nistatine by free or facilitated
pertraction from unfiltered fermentation broths of Streptomyces;
5. separation of cinnamic and p-methoxycinnamic acids by synergetic reactive
extraction and synergetic facilitated pertraction;
6. separation by reactive extraction and facilitated pertraction of vitamin B5
(pantothenic acid);
7. separation by synergetic facilitated pertraction of vitamin B9 (folic acid).
The studied biosynthetic compounds are products of high economically value, as it
was indicated in the studies for 2011 and previsions for the next years made by
specialized companies (Market News Service, In-Pharma Technologist, Nutra
Ingredients Europe, Codex Alimentarius Commission). Besides the above mentioned
objectives, another major objective of the project is to reach top-results in the
field of bioseparations, for increasing the visibility of the Romanian research
activities.
二. 應用/用途
The substance to be separated diffuses through a membrane into a solvent on the other
side. This way of separating liquids does not differentiate much from the method
known as extraction. However there is at least one benefit; the bacteria is separated
from the solvent. This enables the use of a solvent harmful to the bacteria. It is said
that the diffusion of butanol through the membrane is the rate controlling step[20].
However as long as the production rate in the reactor is even lower, this should not be
a problem.
Qureshi, N. and Maddox, I.S. have studied the reduction in butanol inhibition using
perstraction. They used a silica tubing as membrane and oleyl alcohol as solvent. As
substrate they used lactose/whey permeate. Their result was satisfying; a lactose
concentration of 227gL-1 could be used (compared with 28.6gL-1 normally), at this
lactose concentration the productivity was 0.07gL-1. Using perstraction ca. 99
gL-1h-1 (fermentation broth volume) ABE was produced. The experiment was run for
391 hours and the concentration of ABE in the oleyl alcohol was at maximum
9.75gL-1. Figure 5 shows butanol, ethanol and butyric acid concentrations in oleyl
alcohol at various levels of these chemicals in aqueous phase during the experiment.
According to Qureshi, N. and Maddox, I.S no acetone can be found in the organic
solvent.
Figure 5: Butanol, ethanol and butyric acid concentrations in oleyl alcohol at various
levels of these chemicals in aqueous phase during fermentation perstraction
experiment.
In situ product separation in butanol fermentation by membrane-assisted extraction
has been studied by Jeon, Y.J.; Lee, Y.Y.[21]. They used the same membrane and the
same organic solvent as Qureshi, N. and Maddox, I.S. The results of Jeon and Lee are
depicted in table 4.
Table 4: Overall performance of membrane-extractive butanol fermentation
In figure 6 (below), a flow diagram that shows where the perstraction shall be
implemented in the ABE process.
Figure 6: Simplified flow diagram over the ABE process using perstraction.
三. 參考文獻
ADVANCED SEPARATION OF BIOSYNTHETIC COMPOUNDS BY
FACILITATED AND SYNERGETIC PERTRACTION (PERSYNBIO)
Research Grant no. 207/5.10.2011, Project ID: PN-II-IDEI-PCE-2011-3-088
Separation of Biosynthetic Products by Pertraction
Tutors Sixten Dahlbom Hans T. Karlsson Hanna Landgren Christian Hulteberg
Peter Fransson
Alternatives for Bio-Butanol Production
12/5-2011