TWI631153B - Preparation method of bacterial cellulose film using surfactant - Google Patents

Abstract

The present invention relates to a process for the preparation of a bacterial cellulose film having a transmittance of about 90% for light having a wavelength of 550 nm. The preparation method of the present invention is contained in a container filled with a culture solution in which the bacteria have been inoculated, and the bacteria are left to be cultured under the capping of the container for a while until a piece of bacterial cellulose film is formed, wherein the culture solution contains 1000-20000 ppm. Surfactant. The film produced by the present invention can be used as a skin dressing, packaging material or industrial material.

Description

Method for preparing bacterial cellulose film using surfactant

The present invention relates to a method for preparing a bacterial cellulose film, and more particularly to a method for preparing a bacterial cellulose film having a transmittance of about 90% for light having a wavelength of 550 nm.

The bacterial cellulose produced by the fermentation of acetic acid bacteria can increase the thickness of the membrane by increasing the number of culture days, but the thin membrane produced by the short culture time is too soft and easily broken, and the appearance of the membrane is not uniform. Therefore, the thin film is often obtained by a post-processing method such as extrusion or cutting, which increases the time and cost required for the process.

Japanese Patent Publication No. JP2009296979A discloses that the invention utilizes the addition of a nonionic surfactant at a concentration ranging from 0.05 to 300 ppm to increase the yield of the bacterial cellulose membrane (dry film weight). Previously, regardless of the thickness and transparency of the bacterial cellulose film.

A primary object of the present invention is to provide a method of preparing a bacterial cellulose film having a transmittance of about 90% for light having a wavelength of 550 nm.

The method of the invention directly can prepare a bacterial cellulose film, and does not require a post-processing method such as extrusion or cutting to obtain a thin film.

A method for preparing a bacterial cellulose film according to the present invention is contained in a container filled with a culture solution in which bacteria have been inoculated, and the bacteria are allowed to stand for a while under the capping of the container until a piece of bacterial cellulose is formed. The film is characterized in that the culture solution contains 1000-20000 ppm of a surfactant.

Preferably, the bacterium is Gluconacetobacter xylinus.

Preferably, the surfactant is an anionic surfactant.

Preferably, the surfactant is a nonionic surfactant.

Preferably, the nonionic surfactant is lecithin, polyethoxylated sorbitan fatty acid ester under the trade name TWEEN or sorbitan fatty acid ester under the trade name SPAN ).

Preferably, the method of the present invention further comprises removing the bacterial cellulose film from the container; and washing the bacterial cellulose film with an alkaline aqueous solution, and then washing the bacterial cellulose film with water until the pH of the used washing water The value is approximately 7.

Preferably, the method of the present invention further comprises removing the bacterial cellulose film from the container; and washing the bacterial cellulose film with water until the pH of the used washing water is about 7.

Preferably, the period of time is 1-5 days.

Preferably, the bacterial cellulose film has a thickness of from 0.1 to 3.0 mm.

Preferably, the bacterial cellulose film has a transmittance of 80-99% for light having a wavelength of 550 nm.

Preferably, the bacterial cellulose film has a thickness of from 0.1 to 1.0 mm.

Preferably, the bacterial cellulose film has a transmittance of greater than 90% for light having a wavelength of 550 nm.

Preferably, the bacteria-inoculated culture solution located in the container has a liquid surface area of 100 to 1000 cm ² and a thickness of 0.2 to 0.5 cm.

Preferably, the horizontal static culture is carried out for a period of time at room temperature, for example, at a temperature of 25-35 °C.

In a preferred embodiment of the present invention, the culture medium having the inoculated acetic acid bacteria containing 10000 ppm of the surfactant is subjected to static culture for 1.5 to 3 days, and the bacterial fiber having a film thickness of <1 mm, which is not easily broken and has a transparent appearance can be collected. Film, no need for post-processing. In addition, the film is thin and transparent, so the time and cost required for the washing process are greatly reduced, and the transparent bacterial cellulose film can be efficiently produced, and can be applied to skin dressings, packaging materials, or industrial materials such as lithium battery isolation. Membrane, transparent conductive film and filter film, etc. The transparent bacterial cellulose film has a transmittance of light of >90% at a wavelength of 550 nm and a transmittance difference of <0.5% throughout the film.

The preparation method of the invention is to add a low bacteriostatic interface activity In the medium, the cells are uniformly dispersed in the medium, and the bacterial cellulose film having a film thickness of <1 mm, which is not easily broken and has a transparent appearance can be collected by static culture for 1.5 to 3 days. In the method of the present invention, the surfactant-added medium can be placed in a generally open container, and the container is capped and then subjected to static culture. The transparent bacterial cellulose film is formed at the interface between the air and the liquid medium, so that the film can be conveniently taken from the container, washed with water or washed with an alkaline aqueous solution and then washed with water to make the pH of the film approximately 7 A transparent bacterial cellulose film product having a thickness of <1 mm can be prepared.

Surfactants suitable for use in the present invention include, but are not limited to, anionic surfactants, cationic surfactants, amphoteric surfactants, or nonionic surfactants. Nonionic surfactants are preferred, such as lecithin, polyethoxylated sorbitan fatty acid ester under the trade name TWEEN, or sorbitan fatty acid ester under the trade name SPAN ).

Example

The acetic acid bacteria Gluconacetobacter xylinus colonies were inoculated into a 250 mL Erlenmeyer flask containing 100 mL of AC medium (Table 2 below), and cultured at 30 ° C, 100 rpm for 3 days, and then the bacterial solution was taken out and inoculated with 10% by volume (v/v) of the inoculum. 100 mL of liquid media was placed in a nylon box (area 20*20*8.5 cm) and then covered with a lid for box culture. The liquid medium (YE medium) contained the components listed in Table 1 below, and was further added with 1% Tween 80 nonionic surfactant, which is based on the volume of the liquid medium. The box was placed in a flat place at 30 ° C for 2 days to obtain a transparent bacterial cellulose film. hit The lid was opened, the film was taken out from the box, and then washed with reverse osmosis (RO) water at 80 ° C for 10 minutes, and then washed at room temperature until the pH of the film was 7, so that a light having a thickness of 0.8 mm and a wavelength of 550 nm was obtained. A transparent bacterial cellulose film having a penetration of about 90%.

The human eye is most sensitive to light with a wavelength between 550 nm and 560 nm, which is about the dark green color. The eye is most relaxed and comfortable when viewing the color of this range. Therefore, the present embodiment uses a light having a wavelength of 550 nm for the diaphragm. Penetration measurement.

Claims (8)

A method for preparing a bacterial cellulose film, which is contained in a container filled with a culture solution in which bacteria have been inoculated, and the cultured bacteria are allowed to stand under a container for a period of time until a bacterial cellulose film is formed, which is characterized by the culture. The liquid contains 1000-20000 ppm of a non-ionic interface selected from the group consisting of lecithin, polyethoxylated sorbitan fatty acid ester, and sorbitan fatty acid ester. The active agent, and the period of time is 1-5 days, wherein the bacterium is Gluconacetobacter xylinus , the method further comprises removing the bacterial cellulose film from the container, and the bacterial cellulose film removed is 0.1- 3.0mm thickness. The method of claim 1, further comprising washing the removed bacterial cellulose film with an aqueous alkaline solution, and then washing the bacterial cellulose film with water until the pH of the used washing water is about 7. The method of claim 1, further comprising washing the bacterial cellulose film removed with water until the pH of the used washing water is about 7. The method of claim 1, wherein the bacterial cellulose film has a transmittance of 80-99% for light having a wavelength of 550 nm. The method of claim 1, wherein the bacterial cellulose film has a thickness of 0.1 to 1.0 mm. The method of claim 1, wherein the bacterial cellulose film has a transmittance of greater than 90% for light having a wavelength of 550 nm. The method of claim 1, wherein the culture solution inoculated with the bacteria in the container has a liquid surface area of 100 to 1000 cm ² and a thickness of 0.2 to 0.5 cm. The method of claim 1, wherein the horizontal static culture is carried out at a temperature of 25-35 ° C for a period of time.