Modern consumers are becoming more demanding. They are looking for convenience products that will clean their clothes and dishes at lower temperatures, and are sensitive to new functions and product features. On top of that, there is an increased awareness of environmental protection – especially if there are cost savings to be made to energy bills.
One clear trend is that consumers around the globe are washing at ever-lower temperatures (Figure 1). In Europe, the detergents industry has taken a proactive approach to help promote reducing energy consumption among consumers through the International Association for Soaps, Detergents and Maintenance’s (AISE) ‘Wash Right’ campaign. Also, manufacturers themselves have started promotional campaigns to reduce the temperature of washing cycles.
Much of this trend has been driven by the facts:
Washing at 30oC rather than 40oC can save up to 40% of the energy used by a washing machine.
A washing cycle at 60oC requires three times more energy as one at 20oC, and twice as much as a cycle at 40oC.
The trend to lower temperature washing is strongest among young adults below 35 years old.
Lower water consumption is another priority when it comes to clothes washing, with different washing machine designs having a dramatic impact on overall water consumption. Traditional vertical axis washing machines in the US, for example, use roughly 60L of water per wash for the main wash. In comparison, horizontal axis machines common in Europe use only 15L of water for the same cycle, while one recent washing machine design was designed to use a mere 10-12L per wash for the main wash. Other washing machine designs also feature special sensors that adapt the wash programme to factors such as the weight of the load, or the amount of soil in the water. Yet another development is geared at washing machines that allow consumers to set the time for the washing programme, instead of the machine.
Liquid detergents, meanwhile, are becoming increasingly popular around the world. Driven by convenience and appeal to consumer lifestyle, liquid detergents now hold around 84% of the market in the US; about 28% of the market in EU- 27; and a relatively steady 11% share in the rest of the world.
On top of all this, detergent manufacturers strive to reduce packaging material and transport costs, resulting in more concentrated products in smaller bottles or containers. Concentration provides other benefits as well: the water content in the formula can be reduced by up to 45%, but most importantly, more products require less retailer shelf space. Weight efficient chemistry is another driver in detergent product design.
The demand for low temperature washing detergents is a serious challenge. Lowering temperatures will result in poor wash performance unless better ingredients are created that are especially suited to these new, environmentally friendly conditions. These detergents need to work fast, yield high performance soil removal at low temperatures and be increasingly concentrated.
Most detergent ingredients perform less well at temperatures below 40°C. Surfactants tend to precipitate, especially in the presence of soil and at high water hardness, and tend to loose some of their cleaning activities. Most bleach activators do not work below 40°C. The general problem is: If the temperature goes down, soil removal goes down.
However, these deleterious effects of cleaning at lower temperature can be compensated for and even improved with high performance enzymes. Today, proteases used for removing protein stains account for approximately 60% of all enzymes used for detergent manufacturing. Other commonly used enzymes are amylases for starch-based soils, cellulases for basic fabric care, mannanases for the breakdown of galactomannans like guar gum and locust bean gum, and lipases for fatty soil removal.
But with temperatures of washing cycles as low as 20oC in Europe, 10oC in China and 16oC in the US, detergent manufacturers are now looking at enzymes to provide them with new functionalities; premium performance under various conditions (temperature, pH, length of washing cycle, water hardness); and more effective and efficient products.
Based on current trends, the detergents industry is looking for new and innovative solutions that achieve better performance while reducing the number of ingredients. Among other things, it is looking for new surfactants, new formulation chemicals, and/or creating synergies between ingredients that allow for the reduction of surfactants.
Enzymes have a number of advantages for detergent manufacturers. Compared with stoichiometric systems, in which one molecule triggers one specific reaction only once, enzymes can give a higher return on investment, so reducing the number of ingredients needed. Also, enzymes have a higher activity at a lower weight – allowing for a more concentrated product, and thus compaction. Last but not least, by selecting the right type of enzyme, a detergent manufacturer can get better performance at low temperatures.
Basically, today’s consumer is looking for a number of critical performance features that enzymes allow for cold water washing, fatty soil removal, and bleaching; three elements that determine detergent performance in the eyes of the consumer.
Industrial biotechnology companies and enzyme manufacturers play a pivotal role in the development of enzymes for the detergents industry. Enzyme innovation requires a high technology approach. Candidates for new enzymes are selected by high throughput screening approaches, in a development cycle that typically takes 18-24 months. The enzyme is then optimised either by adjusting its threedimensional structure or by tailoring key active sites. Specialist scientists apply multiple biotechnology methods for optimising and tailoring the enzyme to the specific need, after which the prototype product will be scaled up to industrial scale manufacturing volumes by fermentation.
Enzymes, like other detergent ingredients, also show poorer performance at lower washing temperatures. However, we can use protein engineering to design or select the enzyme variants that are particularly suited to perform at reduced temperatures. Selecting the right protease, for example, can boost detergent activity to 40oC performance even when washing at 20oC. It will also close the performance gap when consumers move to shorter washing cycles, meaning that the cleaning will happen earlier in the cycle time
The detergents industry is constantly evolving with the needs of consumers. The trends of cold water washing, reduction in energy consumption and compaction are driving the need for innovative enzymes. Longer term, enzymes can provide the answer to chemical replacement, reducing the impact on the environment even further.
At biotech firm Genencor we are working closely with the detergents industry on new product development.
At this point in time, the company is looking at possibilities around bio-bleaching and biosurfactancy – enzyme functionality that goes beyond traditional cleaning applications by means of the hydrolytic degradation of stains.
Novel applications that go beyond stain removal are being tested and have shown proof of concept in certain applications, but have not yet been commercialised. Bio-surfactancy could result in both cost reductions and performance at low temperatures.
Bio-surfactancy could be generated by enzymes that convert soil into surfactants, thereby increasing surfactancy in the wash when necessary, while keeping ingredients levels down. Similarly in situ generation of bleach by enzymes would allow for omitting traditional bleach – which also performs less well at lower temperatures - in detergent formulations.
Michiel van Zeeland is marketing manager fabric & household care; Marion van Deurzen is manager applications research fabric & household care, and Hans de Nobel is innovation manager at Genencor in Leiden, The Netherlands.