Enzymatic Preparation/Bleaching/Finishing of Cotton
Project Title Enzymatic Preparation/Bleaching/Finishing of Cotton
Continuation Project? X Yes (No. of Prior Years Funded 1)
Research Team LeaderJ. Nolan Etters Phone706-542-4892
Team Leader's Email netters@fcs.uga.edu
Team Leader's InstitutionThe University of Georgia
Industry Partner Contacts:
Mr. Lee S. Bryan, Mount Vernon Mills, Inc., Trion, Ga., (706-734-0518),
Lead Contact
Mr. David Lamb, Springs Industries, Inc., Griffin, Ga., (770-412-5581)
Ms. Kelly Means, Coats North America, Toccoa, Ga., (706-886-2141)
Proposed Research Team:
Researcher Name and Institution Phone
J. Nolan Etters, The University of Georgia (TMI) 706-542-4892
Lars G. Ljungdahl, The University of Georgia (BMB) 706-542-1334
Irina Kataeva, The University of Georgia (BMB) 706-542-1334
Radhakrishnaiah Parachuru, Georgia Institute of Technology 404-894-0029
Requested Funds:
College or University $$ Requested
The University of Georgia (TMI) 46,575
The University of Georgia (BMB) 56,000
Georgia Institute of Technology 28,500
Total TIP-PFFP Funds Requested for FY2003 131,075
Executive Summary
Cotton remains the international fiber of choice among the world's expanding population, with as much as 42 billion pounds of this fiber consumed annually in textile use, and cotton is the most important fiber that is used by Georgia's textile manufacturing industry. There are, however, severe environmental and other costs associated with the widespread use of cotton. Unlike manmade cellulosic fibers such as rayon or lyocell, cotton must be thoroughly prepared for subsequent wet-processing treatments such as mercerizing, bleaching, dyeing, printing, or finishing. The purpose of the preparation step is to make the textile substrate uniformly absorbent, and the traditional method to achieve such absorbency is to scour the substrate with strong solutions of sodium hydroxide at elevated temperatures. Needless to say, traditional caustic scouring contributes significantly to the BOD, COD, TDS, and alkalinity of the effluent. In addition caustic scouring results in unnecessary weight loss of the cotton substrate. In fact, Rößner (Melliand Textilberichte, Vol. 74, No. 2, 1993, pp144-148) notes that about "75% of the organic pollutant level arising from textile finishing is derived from the preparation of cotton goods."
It is useful, therefore, to explore an alternative, commercially viable and cost-effective method for preparing cotton fiber substrates. Such a method is based on the use of biopreparation of cotton substrates by the use of newly discovered, non-cellulose degrading enzymes. It is anticipated that commercial biopreparation of cotton substrates will have substantial positive implications for Georgia's textile manufacturers through the reduction of contributions to the effluent, reduction in processing costs, and improvements in the quality of the cotton textile product. Successful bio-preparation also may lead to successful bio-bleaching of cotton fiber.
Explanation of Work Proposed
a) Description of Critical Industry Problem:
Unlike manmade cellulosic fibers such as rayon or lyocell, cotton must be thoroughly prepared for subsequent wet-processing treatments such as mercerizing, bleaching, dyeing, printing, or finishing. The purpose of the preparation step is to make the textile substrate uniformly absorbent, and the traditional method to achieve such absorbency is to scour the substrate with strong solutions of sodium hydroxide that additionally contain wetting, dispersing, and chelating agents. These strong alkaline solutions are applied at high temperatures, sometimes above the boiling point of water. Such solutions attack the primary wall matrix of the cotton fiber and result in a very high removal of the non-cellulosic components. However, unless the process carefully is controlled, the cotton fiber may be damaged during the scouring process by the formation of oxycellulose. Most cotton that is subjected to caustic scouring develops a harsh hand due to the removal of most of the lubricating wax from the fiber. Needless to say, traditional caustic scouring contributes significantly to the BOD, COD, TDS, and alkalinity of the effluent. Also, caustic scouring results in unnecessary weight loss of the cotton substrate. In addition to the negative environmental impact of the organic pollutant level that caustic scouring causes, much time and water are needed to rinse sodium hydroxide from the cotton. It is believed that the replacement of caustic scouring of cotton substrates by biopreparation with selected enzymes will result in the following quantifiable improvements: Lower, BOD, COD, TDS, Alkalinity, Process Time, Cotton Weight Loss, and Harshness of Hand.
b) Measurable Objectives for FY2003:
(1) Building on information obtained during FY 2002, move into further pilot scale development of pectinase biopreparation formulas and begin transfer to commercial environments.
(2) Comparison of BOD, COD, TDS, Alkalinity, Process Time Weight Loss, and Harshness of Hand resulting from conventional caustic scouring and from biopreparation of cotton substrates.
(3) Begin screening of enzymes for use in bio-bleaching of cotton fiber, and seek means to combine both preparation and bleaching by enzymatic processes.
c) Project end Measurable Objectives:
It is anticipated that by the conclusion of this project, a substantial portion of the cotton used by Georgia's textile manufacturing industry will be bio-prepared/bio-bleached by the use of enzymes, resulting in greatly decreased contribution to the effluent, improved cost savings in cotton processing, and an improved, added value cotton textile product.
d) Past and Current Basis for Proposed Work:
The cotton fiber primary wall is responsible for the lack of water absorbency of the fiber
when no wetting agents are included in the various aqueous processing baths. It is well known that the wax in the cotton fiber primary wall is a source of the hydrophobic nature of unscoured cotton. In addition to waxes, insoluble calcium, magnesium, iron, and other salts of polygalacturonic acids (pectins) contribute to the hydrophobic nature of unscoured cotton fiber. These pectate salts also act as biological glue, binding the non-cellulosic components of the primary wall within the cellulosic matrix. The non-cellulosic components of the primary wall need not be uniformly distributed in the cross-section of the wall. In fact, it is more likely that the concentration of these components increases as the outer zone of the wall is approached to produce a cuticle.
Although cellulase is beneficial for bio-polishing of fabric to achieve a smooth appearance or in treatment of denim fabric to simulate the stone-washed look, cellulase is not the best choice for biopreparation. When cotton fiber is treated with an aqueous solution of cellulase, the enzyme is adsorbed onto the surface of the fiber to form a primary wall/cellulase complex. At the interface, hydrolysis of the cellulose occurs very rapidly, releasing products of decomposition of cellulose and also non-cellulosic components which were dispersed within the primary wall matrix. The process is repeated over and over at an extremely rapid rate, producing pathways in the primary wall that permit the enzyme to reach and accelerate hydrolysis of the cellulose that constitutes the very substance of the cotton fiber - the secondary wall. It is clear that enzymatic destruction of cotton by the use of cellulase will result in an absorbent fiber - but at the expense of a much weight and strength loss.
An extremely powerful alkaline pectinase recently has been isolated. This new enzyme is now being produced in volume and is being reduced to commercial use in biopreparation on a worldwide basis. The major benefit of this enzyme in biopreparation is that the enzyme does not destroy the cellulose of the cotton fiber. The enzyme is a pectate lyase, and as such very rapidly catalyzes hydrolysis of salts of polygalacturonic acids (pectin's) in the primary wall matrix. The term alkaline pectinase is used to describe the enzyme because the biological catalyst is used under mildly alkaline conditions which are very beneficial in preparation processes. It is known that alkaline conditions inactivate other pectinases. As the biological glue is hydrolyzed, the other non-cellulosic components of the primary wall are released and are dissolved, dispersed, or emulsified by the surfactants and mild chelating agents in the biopreparation bath.
The result of biopreparation with alkaline pectinase is that the cellulose is not degraded, resulting in less weight or strength loss than occurs with either caustic scouring or cellulase treatment. In addition, the amount of wax removed is not so high as that which occurs with the other processes, resulting in an improved hand. Work preformed during FY2002 has confirmed that the subject pectinase enzyme is an extremely powerful agent for bio-preparation of cotton fiber, and suggests that pathways for the enzymatic bleaching of cotton also are worth pursuit. It is known, for example, that peroxidases, glucose oxidases, laccases, and xylanases have been explored for use in bleaching cotton. Researchers in the Department of Biochemistry and Molecular Biology (BMB) at The University of Georgia have found that enzymes such as xylanases, esterases, and some cellulases increase the whiteness of paper pulp. It is possible that these enzymes - either separately or in combination - may result in sufficient bleaching of cotton fiber without the associated damage that occurs with harsh peroxide processes. Indeed, Glycosyl hydrolases may offer a key for successful enzymatic bleaching.
e) Industry Partner Involvement:
Industry partners will provide cotton substrates for use in laboratory investigations designed to optimize the types and concentrations of enzymes for use in biopreparation. Plant trials will be performed in the industry partners' plants to test the effectiveness of the developed biopreparation formulas and procedures.
Description of Technical Approach
a) Work Plan Description:
Laboratory supplies of different classes of enzymes, e.g. pectinases, proteases, cellulases, will be obtained from various suppliers and tested for their effectiveness in the promotion of biopreparation of cotton substrates. The enzymes will be screened and optimum formulas and procedures will be developed. After optimum formulas have been developed in the laboratory, production trials will be made in the industry partners' facilities. Based on the results obtained, necessary modifications of the biopreparation formulas and procedures will be made and additional plant trials will be run. In the case of biopreparation of woven fabrics, it may be possible to combine both desizing and biopreparation into one step. This desirable objective will be explored.
b) Equipment and Facilities:
As far as it is known, most laboratory equipment and facilities needed for this investigation are in place. Chromatographic columns will, however, have to be purchased. No anticipated changes in production equipment are evident.
c) Transfer of Information Obtained in the Investigation:
(1) presentation of findings and written reports to management of the specific companies listed.
(2) presentations of findings at the mid-year TIP-PFFP meeting.
(3) presentations of findings at AATCC local and national meetings
(4) annual report to TIP-PFFP Coordinator
(5) publication of findings in appropriate textile journals such as: America's Textiles International, AATCC Review Textile World, and other publications.
Description of Project Team
J. Nolan Etters:
Dr. Etters worked in the primary textile industry (Dan River Inc.) for 23 years as a research chemist in dyeing applications technology before joining academia in 1986. One of his recent research focuses at UGA has been enzyme use in textiles and dyeing characteristics of enzymatically prepared cotton. He has published several papers in this area. Dr. Etters was 1994 recipient of AATCC's highest award for achievement in textile chemistry, The Olney Medal.
Lars Ljungdahl:
Dr. Ljungdahl is a Georgia Power Distinguished Professor of Biotechnology in the Department of Biochemistry and Molecular Biology (BMB) at The University of Georgia. He is an internationally recognized enzymologist and has developed a base of technology in the use of enzymes in bleaching paper. He will oversee work in the area of enzymatic bleaching of cooton and will coordinate this aspect of the work with other project objectives.
Irina Kataeva:
Dr. Kataeva has worked with biochemistry and enzymes for years. She is a research associate of Dr. Ljungdahl and will set up research protocols and oversee the work of the Post-Doc. in the areas of: Enzyme purification, acitivity, and measurement of release of colored substances from cotton.
R. Parachuru:
Dr. Parachuru, a research scientist in the School of Textile and Fiber Engineering at Georgia Institute of Technology, is recognized internationally for his expertise in the area of objective evaluation of subjective fabric properties such as handle and comfort. He also is an expert in yarn and fabric manufacturing technologies, and is very knowledgeable in the area of structure-property relationships of textile materials.
Schedule
Months Project Activity
July - August Continue to develop pilot scale formulas for biopreparation, and begin screening of candidate enzymes for bio-bleaching.
July - December Move into plant trials with bio-preparation and continue to screen enzymes for effectiveness in decolorizing cotton.
January Presentation of initial findings at Mid-term TIP-PFFP conference.
December - June Continue laboratory work and plant trials.
December - June Discuss
with industry partners the direction of project and obtain input
with regard to any change of project focus.
Project Summary:
A team of researchers at The University of Georgia and The Georgia Institute of Technology are collaborating on a State funded textile chemical project that has potential to reduce textile effluent, while improving the quality of the textile substrate. The research is focused on the use of enzymes to prepare, bleach, and finish cotton fiber in yarn and fabric form. So far the research has revealed that cotton fiber can be prepared for dyeing and other processes by the uses of pectinase enzyme. Since use of the gentle enzyme process replaces the need for harsh processing with sodium hydroxide, there is less contribution to the textile effluent and a softer textile product. The project is being expanded to include bio-bleaching during FY2003
