Enzymes and GOTS

9 12 2011

Last week we reviewed the ways enzymes are helping to give textile processes a lighter footprint while at the same time producing better finished goods – at a lower cost.  Seems to be a win/win situation, until you begin to unpeel the onion:

It begins with the production of the enzyme:  Enzymes have always been obtained from three primary sources, i.e., animal tissue, plants or microbes.  By starting with the primary source and “feeding” it properly (known as fermentation), we ended up with our target product – like beer, for example.

But these naturally occurring enzymes are often not readily available in sufficient quantities for  industrial use. The production of enzymes – including microorganisms used to produce enzymes –  is a pursuit central to the modern biotechnology industry.  Until recently, the availability of enzymes  have been limited to the quantities that could be produced in the host organism in which they were naturally derived.

Today, the starting point is a vial of a selected strain of microorganisms – microbial hosts which have been selectively bred by industry. They will be nurtured and fed until they multiply many thousand times.  Once fermentation is complete, the microorganisms are destroyed, the desired enzymes are recovered from the fermentation broth and sold as a standardized product.

Modern biotechnology has improved enzyme production and enzyme quality in several ways:

1)     Increased efficiency of enzyme production resulting in higheryields;

2)     Increased enzyme purity through reduction or elimination of side activities;

3)     Enhancing the function of specific enzyme proteins, e.g., by increasing the temperature range over which an enzyme is active.

The results, as we discussed last week,  are better products, produced more efficiently, often at lower cost and with less environmental impact.

It wasn’t until genetic engineering came about that these biological methods became economically viable. Targeted genetic manipulation has not only enhanced the productivity of these methods, it also has resulted in the production of substances that were previously impossible. To date, up to 60% of all technical enzymes are produced with genetically modified organisms (GMO) – and this number is sure to increase given that GMO-based enzyme production requires 40-50% less energy and raw materials than traditional enzyme production.[1]  And therein lies the rub.

Cheese, eggs and milk, for example, may not be genetically modified themselves but may contain ingredients and additives that were produced from genetically modified microorganisms.

Take cheese for example: Traditionally, this enzyme preparation, sometimes known as rennin, was extracted from calf stomachs. The active ingredient is chymosin, an enzyme produced in the stomach of suckling calves needed for breaking down cow’s milk.

It is now possible to produce chymosin in genetically modified fungi. These modified microorganisms contain the gene derived from the stomach of calves that is responsible for producing chymosin. When grown in a bioreactor, they release chymosin into the culture medium. Afterwards, the enzyme is extracted and purified yielding a product that is 80 to 90 percent pure. Natural rennin contains only 4 to 8 percent active enzyme.[2]

Even the nutritive medium used to grow bacteria and fungi is often made from GMOs.

Again, what are the arguments against GMO?

Briefly, because I want to get to how this pertains to the textile industry, here are the most common concerns :

1)     What happens when these GMOs interact with other organisms?  Already there is concern that GMO crops resistant to weed killers will themselves become uncontrolled weeds in other fields – the GMO plant may cross pollinate with a related species that is a weed which then becomes resistant to weed killers.  This is already happening according to many published reports.  And it can happen in really subtle ways:

  1. Since 1986, Novo Nordisk, one of the world’s largest producers of industrial enzymes,  has processed the residuals of fermentation processes generated by GMOs into “biomass” or “sludge” called NovoGro. The sludge is dehydrated and freely distributed among farmers. NovoGro is virtually the company’s only possibility to dispose of its massive enzyme production waste. In 1996, 2.2 million cubic meters of NovoGro were produced. Daily about 150 truckloads of NovoGro are spread over 70 hectares of land in Denmark .  Total costs are about US$ 13 million per year, all carried by Novo Nordisk. A Danish farmers’ organization protested against the distribution of NovoGro because it suspected pollution by GMOs. There are concerns that risks associated with the use of GMO products is not worth the benefits as long as the environmental impacts are not monitored by third parties.[3]

2)     The argument rages about the human health risks of genetically engineered foods – specifically with regard to the rise in food allergies. The British Medical Association (BMA)  in a study done in 2003, concluded that the risks to human health associated with GMO foods is negligible, while calling for further research and surveillance.[4]

3)     Ethical concern of the “slippery slope”: because it appears to provide costless benefits, so companies and governments may rush into production one or more products of the new technologies that will turn out to be harmful, either to the environment or to humans directly.

The manufacturers and scientists tell us that there are no traces of these GMO microorganisms in the final product, and no microbial DNA is detectable.

Additives (such as enzymes) that are produced with the help of genetically modified microorganisms do not require labeling because GMOs are not directly associated with the final product.  In the textile industry, they are known as auxiliaries or processing aids.

In textiles, the Global Organic Textile Standard (GOTS) has stated that the use of genetically modified organisms – including their enzymes – is incompatible with the production of textiles labelled as ‘organic’ or ‘made with organic’ under GOTS.  According to the GOTS website:  “While the IWG Technical Committee acknowledges that there are applications including, and based on GM technologies, that result in a reduction of energy and water use and replace chemicals compared to some conventional textile processes this is only one side of the coin.”  They go on to say that it is important to give consumers a choice to actively decide for themselves if they want to purchase a textile product made without using any GMO derived inputs.

As a company which is trying to do the right thing, I don’t know where I stand on this issue.    What do you think?





Enzymes in textile processing

2 12 2011

Humankind has used enzymes for thousands of years to carry out important chemical reactions for making products such as cheese, beer, and wine. Bread and yogurt also owe their flavor and texture to a range of enzyme producing organisms that were domesticated many years ago.

In the textile industry, one of the first areas which enzyme research opened up was the field of desizing of textiles.  A size is a substance that coats and strengthens the fibers to prevent damage during the weaving process. Size is usually applied to the warp yarn, since this is particularly prone to mechanical strain during weaving.   The size must be removed before a fabric can be bleached and dyed, since it affects the uniformity of wet processing. Previously, in order to remove the size, textiles were treated with acid, alkali or oxidising agents, or soaked in water for several days so that naturally occurring microorganisms could break down the starch. However, both of these methods were difficult to control and sometimes damaged or discoloured the material. But by using enzymes, which are specific for starch, the size can be removed without damaging the fibers.

Enzymes used in textile processing - photo from Novozymes

It represented great progress, therefore, when crude enzyme extracts in the form of malt extract, or later, in the form of pancreas extract, were first used to carry out desizing.  Bacterial amylase derived from Bacillus subtilis  was used for desizing  as early as 1917. Amylase is a hydrolytic enzyme which catalyses the breakdown of dietary starch to short chain sugars, dextrose  and maltose.

Enzymes have been used increasingly in the textile industry since the late 1980s. Many of the enzymes developed in the last 20 years are able to replace chemicals used by mills. The first major breakthrough was when enzymes were introduced for stonewashing jeans in 1987 – because more than one billion pairs of denim jeans require some sort of pre-wash treatment every year. Within a few years, the majority of denim finishing laundries had switched from pumice stones to enzymes.

Today, enzymes are used to  treat and modify fibers, particularly during textile processing and in caring for textiles afterwards.  They are used to enhance the preparation of cotton for weaving, reduce impurities, minimize “pulls” in fabric, or as pre-treatment before dying to reduce rinsing time and improve color quality.  New processing applications have been developed for:

  • Scouring (the process of removing natural waxes, pectins, fats and other impurities from the surface of fibers), which gives a fabric a high and even wet ability so that it can be bleached and dyed successfully. Today, highly alkaline chemicals (such as caustic soda) are used for scouring. These chemicals not only remove the non-cellulosic impurities from the cotton, but also attack the cellulose leading to heavy strength loss and weight loss in the fabric. Furthermore, using these hazardous chemicals result in high COD (chemical oxygen demand) and BOD (biological oxygen demand)  in the waste water. Recently a new enzymatic scouring process known as ‘Bio-Scouring’ is being used in textile wet-processing with which all non-cellulosic components from native cotton are completely or partially removed. After this Bio-Scouring process, the cotton has an intact cellulose structure, with lower weight loss and strength loss. The fabric gives better wetting and penetration properties, making the subsequent bleach process easy and  giving much better dye uptake.
    • One of the newest products, PrimaGreen® EcoScour from Genencor, offers sustainability advantages for eco-scouring in cotton pretreatment, including 30 percent water savings and 60 percent energy savings compared to standard processing. In addition, the mild processing conditions result in improved fabric quality and enhanced color brightness after dyeing.
  • Bleaching – When bleaching cotton, a lot of chemicals, energy and water are part of the process. The company Huntsman has developed a wetter/stabilizer that maximizes the wetting and detergency of the bleaching process and a one-bath caustic neutralizer and peroxide remover in order to shorten the bleaching cycle, reduce energy and water required and deliver more consistent bleaching results. They have developed surfactants that are environmentally friendly (in that they do not contain Alkylphenol ethoxylates), and the system is both Oeko-Tex and GOTS approved.  After fabric or yarn bleaching, residues of hydrogen peroxide are left in the bath, and need to be completely removed prior to the dyeingprocess, using a step called bleach cleanup.  The traditional method is to neutralize the bleach with a reducing agent, but the dose has to be controlled precisely. Incomplete peroxide removal results in poor dyeing with distinct change of color shade and intensity, as well as patchy, inconsistent dye distribution. Enzymes used for bleach clean-up ensure that residual hydrogen peroxide from the bleaching process is removed efficiently – a small dose of catalase breaks hydrogen peroxide into water and oxygen.  This results in cleaner waste water and reduced water consumption.
    • In 2010, a life-cycle assessment was completed comparing PrimaGreen enzymatic bleaching to conventional textile bleaching methods. According to this LCA, if the enzymatic system were to see wide scale global adoption, the potential savings in freshwater consumption could be up to 10 trillion liters of water annually, and greenhouse gas reductions could range from 10-30 million metric tons. (1)
  • Biofinishing or biopolishing (removing fiber fuzz and pills from fabric surface) –  enzymatic biofinishing yields a cleaner surface, softer handfeel, reduces pilling and increases luster;
  • Denim finishing – In the traditional stonewashing process, the blue denim was faded by the abrasive action of pumice stones on the garment surface. Nowadays, denim finishers are using a special cellulase.  Cellulase works by loosening the indigo dye on the denim in a process known as ‘Bio-Stonewashing’. A small dose of enzyme can replace several kilograms of pumice stones. The use of less pumice stones results in less damage to garment, machine and less pumice dust in the laundry environment; in addition, it’s possible to fade denim without risk of damaging the garment.
  • European scientists have just announced a new and environmentally friendly way to produce textile dyes using enzymes from fungi. (2)

Because of the properties of enzymes, they make the textile manufacturing process much more  environmentally benign. (3)   Generally, they:

  1. operate under milder conditions (temperature and pH) than conventional process chemicals – this results in lower energy costs ( up to 120 kg CO2 savings per ton of textile produced) (4) ;
  2. save water – reduction of water usage up to 19,000 liters per ton of textiles bleached;
  3. are an alternative for toxic chemicals, making wastewater easier and cheaper to treat.
  4.  are easy to control;  do not attack the fiber structure with resulting loss of weight, resulting in better quality of material;
  5. better and more uniform affinity for dyes;
  6. contribute to safer working conditions through elimination of chemical treatments during production processes;
  7. are fully biodegradable.

So why is there a ruckus about enzymes being used in textile processing by GOTS and other organic certifying agencies?

(1)   http://primagreen.genencor.com/sustainability/lca_results/

(2)   http://www.just-style.com/news/eco-friendly-textile-dyes-use-enzymes-from-fungi_id112195.aspx

(3)   http://www.textiletodaybd.com/index.php?pid=magazine&id=52

(4)  http://www.europabio.org/sites/default/files/pages/lutz-walter-benefits-from-white-biotechnology-applications-in-the-european-textile-and-clothing-industry.pdf





White biotechnology and enzymes

18 11 2011

For tens of thousands of years, humans relied on nature to provide them with everything they needed to make their lives more comfortable -cotton and wool for clothes, wood for furniture, clay and ceramic for storage containers, even plants for medicines. But this all changed during the first half of the twentieth century, when organic chemistry developed methods to create many of these products from oil.  Oil-derived synthetic polymers, colored with artificial dyes, soon replaced their precursors from the natural world.

But today, with growing concerns about the dependence on imported oil and the awareness that the world’s oil supplies are not limitless, coupled with stricter environmental regulations,  chemical and biotechnology industries are exploring nature’s richness in search of methods to replace petroleum-based synthetics.  As with other forms of biotechnology, industrial biotech involves engineering biological molecules and microbes with desirable new properties. What is different is how they are then used: to replace chemical processes with biological ones. Whether this is to produce chemicals for other processes or to create products such as biopolymers with new properties, there is a  huge effort to harness biology to accomplish what previously needed big, dirty chemical factories, but in cleaner and greener ways.

The public has for a long time perceived biotechnology to mean dangerous meddling with the genes in food and fiber crops.  But biotechnology is about much more than transgenic crops – it also uses microbes to make pharmaceuticals, for example.  Industrial biotechnology is known as “white” biotechnology, as distinct from “red” biotechnology, which is devoted to medical and pharmaceutical purposes, and “green” biotechnology, or the application of biotechnology in agriculture.

From: EuropaBio

Today, the application of biotechnology to industrial processes holds many promises for sustainable development.  One of the first goals on white biotechnology’s agenda has been the production of biodegradable plastics, and in textiles,  DuPont has invested much in the production of textile fibers from corn sugar (Sorona ®) while Cargill Dow has introduced NatureWorks ™, a polymer made from lactic acid which is used in textiles under the brand name Ingeo ®.  And these new processes have resulted in considerable environmental benefits:  In the case of Sorona ®, for example,  DuPont was able to replace the toxic elements of ethylene glycol and carbon monoxide in typical PET fibers with benign corn sugars.

But there are challenges pertaining to these new bioplastics, and the evidence that they’re actually better for the planet is hotly debated.  As Jim Thomas argues in the New Internationalist online magazine:

Strictly speaking a bioplastic is a polymer that has been produced from a plant instead of from petroleum. That is neither a new breakthrough nor a guarantee of ecological soundness. The earliest plastics such as celluloid were made from tree cellulose before petroleum proved itself a cheaper source. Today, with oil prices skyrocketing, it’s cheaper feedstock –  not green principles –  that is driving chemical companies back to bio-based plastics. Bioplastics may bring in the greenbacks for investors but are they actually green for the planet? The evidence is not convincing. For a start bioplastics may or may not be degradable or biodegradable – two terms that mean very different things. Many bio-based plastics – like DuPont’s Sorona – make no claims to break down in the environment. So much for disposal. But replacing fossil fuels with plants has to be a good idea, right? This is the premise on which the green claims of bioplastics mostly rest. Unfortunately, as advocates of biofuels have learned, switching from oil to biomass as the feedstock of our industrial economy carries its own set of problems. Like hunger.

There is nothing sustainable or organic about most industrial agriculture feedstocks. At present genetically modified corn grown using pesticides is probably the leading source of starch for bioplastics.  The link between genetic contamination and bioplastics is strong.

As concerns mount, the Sustainable Biomaterials Collaborative (SBC) – a network of 16 civil society groups and ethical businesses – is working to define a truly sustainable bioplastic. One of its founders, Tom Lent, explains that the SBC started because ‘the promise of bioplastics was not being realized’.

But biotechnology is not just about bioplastics – it’s actually mostly, these days,  about enzymes.  Biotechnology can provide an unlimited and pure source of enzymes as an alternative to the harsh chemicals traditionally used in industry for accelerating chemical reactions. Enzymes are found in naturally occurring microorganisms, such as bacteria, fungi, and yeast, all of which may or may not be genetically modified.  (We’ll come back to this important point later.)

But what are enzymes?

Enzymes are large protein molecules that  act as  catalysts – substances that start or accelerate chemical reactions without themselves being affected —  and help complex reactions occur everywhere in life.  By their mere presence, and without being consumed in the process, enzymes can speed up chemical processes – reactions occur about a million times faster than they would in the absence of an enzyme. In principle, these reactions could go on forever, but in practice most enzymes have a limited life.   There are many factors that can regulate enzyme activity, including temperature, activators, pH levels, and inhibitors.

Enzymes play a diversified role in many aspects of everyday life including aiding in digestion and the production of food as well as in industrial applications. Enzymes are nature’s catalysts. Humankind has used them for thousands of years to carry out important chemical reactions for making products such as cheese, beer, and wine. Bread and yogurt also owe their flavor and texture to a range of enzyme producing organisms that were domesticated many years ago.

Enzymes are categorized according to the compounds they act upon. Some of the most common include:

  •  proteases which break down proteins,
  •  cellulases which break down cellulose,
  •  lipases which split fats (lipids) into glycerol and fatty acids, and
  •  amylases which break down starch into simple sugars.  Human saliva, for example, contains amylase, an enzyme that helps break down starchy foods into sugars.

In textile treatment, the first enzyme applications, as early as 1857, was the use of barley for removal of starchy size from woven fabrics. The first microbial amylases were used in the 1950s for the same desizing process, which today is routinely used by the industry.

Enzymes are now widely used to prepare the fabrics that your clothing, furniture and other household items are made of.  Increasing demands to reduce pollution caused by the textile industry has fueled biotechnological advances that have replaced harsh chemicals with enzymes in many textile manufacturing processes.  The use of enzymes not only make the process less toxic (by substituting enzymatic treatments for harmful chemical treatments) and eco-friendly, they reduce costs associated with the production process, and consumption of natural resources (water, electricity, fuels), while also improving the quality of the final textile product.

But how do they work?

Rader’s Chem4Kids.com website  has a great explanation, which I’ve quoted below:

Think of enzymes as similar to keys which can open locks.  Just as when you need a key that is just the right shape to fit in a particular lock, enzymes complete very specific jobs and do nothing else.  

From: Chem4Kids

 They are very specific locks and the compounds they work with are the special keys. In the same way there are door keys, car keys, and bike-lock keys, there are enzymes for neural cells, intestinal cells, and your saliva.

Here’s the deal: there are four steps in the process of an enzyme working. 

  1.  An enzyme and a substrate are in the same area. The substrate is the biological molecule that the enzyme will attack. 
  2.  The enzyme grabs onto the substrate with a special area called the active site.  The active site is a specially shaped area of the enzyme that fits around the substrate. The active site is the keyhole of the lock. 
  3. A process called catalysis happens. Catalysis is when the substrate is changed. It could be broken down or combined with another molecule to make something new. 
  4.  Then the enzyme lets go.  When the enzyme lets go, it returns to normal, ready to do another reaction. But the substrate is no longer the same – the substrate is now called the product.

Next, well take a look at how enzymes are helping to make the textile industry’s environmental footprint a bit more benign.