JP2009142265A5

JP2009142265A5 -

Info

Publication number: JP2009142265A5
Application number: JP2008282820A
Authority: JP
Filing date: 2008-11-04
Publication date: 2011-12-22

Description

すなわち、本発明は、次の（１）〜（６）から構成される。
（１）微生物の発酵培養により培養液中に生産された乳酸を精製する工程を含む乳酸の製造方法であって、ｐＨを７以下とした該培養液をナノフィルターに通じて濾過して、ＡＰＨＡ単位色数が２００以下の着色度である乳酸溶液を得る工程Ａを含む、乳酸の製造方法。
（２）前記ナノフィルターの機能層がポリアミドを含む、（１）に記載の乳酸の製造方法。
（３）前記ポリアミドが架橋ピペラジンポリアミドを主成分とし、かつ、化学式１で示される構成成分を含有することを特徴とする（２）に記載の乳酸の製造方法。 That is, this invention is comprised from following (1)-( 6 ).
(1) A method for producing lactic acid comprising a step of purifying lactic acid produced in a culture solution by fermentation culture of microorganisms, wherein the culture solution having a pH of 7 or less is filtered through a nanofilter to obtain APHA. A method for producing lactic acid, comprising the step A of obtaining a lactic acid solution having a coloring degree of 200 or less unit colors.
(2) The method for producing lactic acid according to (1), wherein the functional layer of the nanofilter contains polyamide.
(3) The method for producing lactic acid according to (2), wherein the polyamide contains a cross-linked piperazine polyamide as a main component and a constituent represented by Chemical Formula 1.

（式中、Ｒは−Ｈまたは−ＣＨ_３、ｎは０から３までの整数を表す。）
（４）前記工程Ａにおける培養液の濾過圧が０．１ＭＰａ以上、８ＭＰａ以下である、（１）から（３）のいずれかに記載の乳酸の製造方法。
（５）前記工程Ａで得られる乳酸溶液を、さらに、１Ｐａ以上、大気圧以下の圧力下において、２５℃以上２００℃以下で蒸留する工程に供する、（１）から（４）のいずれかに記載の乳酸の製造方法。
（６）前記培養液に活性炭を添加する工程Ｂと、該工程Ｂの後に定性濾紙で濾過する工程Ｃの後に得られる乳酸を含む分離液を前記工程Ａに供する、（１）から（５）のいずれかに記載の乳酸の製造方法。 (In the formula, R represents —H or —CH ₃ , and n represents an integer of 0 to 3. )
(4 ) The method for producing lactic acid according to any one of (1) to ( 3 ), wherein the filtration pressure of the culture solution in the step A is 0.1 MPa or more and 8 MPa or less.
( 5 ) The lactic acid solution obtained in the step A is further subjected to a step of distillation at a pressure of 1 Pa or higher and an atmospheric pressure or lower at a temperature of 25 ° C. or higher and 200 ° C. or lower. (1) to ( 4 ) The manufacturing method of lactic acid as described.
( 6 ) The separation liquid containing lactic acid obtained after Step B of adding activated carbon to the culture solution and Step C of filtering with qualitative filter paper after Step B is subjected to Step A. (1) to ( 5 ) The method for producing lactic acid according to any one of the above.

本発明の乳酸の製造方法の工程Ａでは、ナノフィルターによる濾過に供する培養液のｐＨを７以下とする。ナノフィルターは、一般に溶液中にイオン化している物質の方が、イオン化していない物質に比べて除去または阻止しやすいことが知られている。培養液のｐＨを７以下とすることで、乳酸が培養液中で解離して乳酸イオンとして存在している割合を少なくし、乳酸が透過しやすくすることができる。好ましくは、培養液のｐＨ４を以下とする。さらに、乳酸のｐＫａが３．８６であることから、ｐＨを３．８６以下とすることで、解離していない乳酸の方が乳酸イオンより培養溶液中に多く含まれるため、効率的に乳酸を透過することができることから、より好ましい。
In step A of the method of manufacturing the lactic acid of the present invention, the pH of the culture solution subjected to filtration through a nanofilter and 7 below. It is known that a nanofilter is generally easier to remove or prevent a material that is ionized in a solution than a material that is not ionized. By setting the pH of the culture solution to 7 or less, the proportion of lactic acid dissociated in the culture solution and present as lactic acid ions can be reduced, and the lactic acid can easily permeate . Good Mashiku shall be below pH4 of culture. Furthermore, since the pKa of lactic acid is 3.86, by setting the pH to 3.86 or less, lactic acid that is not dissociated is more contained in the culture solution than lactic acid ions. Since it can permeate | transmit, it is more preferable.

Claims

A method for producing lactic acid comprising a step of purifying lactic acid produced in a culture solution by fermentation culture of microorganisms, wherein the culture solution having a pH of 7 or less is filtered through a nanofilter, and the APHA unit color number A process for producing lactic acid, comprising the step A of obtaining a lactic acid solution having a coloring degree of 200 or less.

The method for producing lactic acid according to claim 1, wherein the functional layer of the nanofilter contains polyamide.

The method for producing lactic acid according to claim 2, wherein the polyamide comprises a crosslinked piperazine polyamide as a main component and a constituent represented by the chemical formula 1.

(In the formula, R represents —H or —CH ₃ , and n represents an integer of 0 to 3.)

The method for producing lactic acid according to any one of claims 1 to 3 , wherein the filtration pressure of the culture solution in the step A is 0.1 MPa or more and 8 MPa or less.

The lactic acid solution according to any one of claims 1 to 4 , wherein the lactic acid solution obtained in the step A is further subjected to a step of distillation at a temperature of 25 ° C or higher and 200 ° C or lower under a pressure of 1 Pa or higher and atmospheric pressure or lower. Method.

A step B of adding activated carbon to the culture solution, the subjecting the separated liquid containing lactic acid obtained after step C, and filtering the qualitative filter paper after B in the step A, according to any one of claims 1 to 5 Of producing lactic acid.