EFFECT OF SELECTED ON PERFORMANCE OF LIQUID LAUNDRY DETERGENTS

Anita Bocho-Janiszewska University of Technology and Humanities in Radom, Faculty of Materials Science and Design, Department of Chemistry, Corresponding address: Chrobrego Str. 27, 26-600 Radom, Poland, [email protected]

Abstract : The article examines the effect of type of selected enzymes on the performance of liquid laundry detergents. Enzymes are the catalysts of biological processes. Like any other catalyst, an brings the reaction catalyzed to its equilibrium position more quickly than it would occur otherwise. The most widely used detergent enzymes are hydrolases, which remove soils consisting of proteins, lipids, and poly-saccharides. Soil and stain components with good water are easily removed during the cleaning process. Most other stains are partially removed by the system of a detergent, although the result is often unsatisfactory. In most cases a suitable detergent enzyme aids the removal of soils and stains. Whereas the detergent components have a purely physicochemical action, enzymes act by degrading the dirt into smaller and more soluble fragments. In the research samples of liquid containing selected hydrolases (lipase, and ) were prepared. Tests of the performance of liquid laundry detergents: viscosity, foaming properties and washing properties were conducted. Studies were carried out at three differe nt temperatures: 20, 30 and 40° C. For the sake of comparison, the same tests were also performed for a commercially available product. The addition of the enzyme does not affect the viscosity and foaming ability of the liquid laundry detergent. The ability to remove stains by the liquids containing enzymes was high even at a lower temperature. Nevertheless, the complete removal of the stain requires the joint action of the enzyme and the surfactant system.

Keywords: liquid laundry detergents, enzymes, hydrolases, washing ability, foaming properties.

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1. INTRODUCTION

Liquid detergents are convenient products. Compared with powdered detergent they dissolve more rapidly, particularly in cold water, they generate less dust and they are easier to dose. A typical liquid laundry detergent consists all or some of the following components: , builders, optical brighteners, polymers and enzymes [Lai 1997, Smulders 2002, Aehle 2004]. Both anionic and nonionic surfactants are used in the formulations of liquid detergents. Surfactants are primarily responsible for wetting the surfaces of fabrics as well as a soil, helping to lift the stains off the fabric surface and suspend dirt particulates in solution [Broze 1999, Smulders 2002, Tadros 2005]. Builders are introduced into detergents mainly to sequester the hardness of the water. Common builders used are phosphorus compounds (in regions where they are still permitted in detergent products – these compounds have been identified as possible cause of eutro-phication of lakes and rivers and they are severely controlled and even banned in several countries), carbonates, zeolites, salts of polyacetic acid (EDTA) and citrates [Smulders 2002, Mahrholz, Klein and Klein 2004, Yangxin, Jin and Bayly 2008]. Polymers are used in liquid laundry detergents as soil antiredeposition agents, soil release agents and dye transfer inhibitors. Frequently used polymers are carboxymethyl (CMC) derivatives, polyethylene terephthalate and polyoxyethyleneterephthalate (PET-POET polymer) and polyvinylpyrrolidone (PVP) [Bertleffet et al. 1998, Smulders 2002, Lai 1997]. Enzymes improve cleaning performance by degrading large complex molecules such as proteins, starches and fats. The reaction products are more soluble in the washing liquor and can be removed by the surfactants more

8 efficiently. Enzymes also help to maintain whiteness and brightness and clarify colors by removing fuzz. They even can improve fabric softness [Maase and van Tilburg 1983, Olsen and Falholt 1998, Aehle 2004, Zhanget et al. 2014]. Enzymes are proteins. These large organic molecules are produced by all living cells. They catalyze most chemical reactions in biological systems, usually at low temperature and at the neutral pH, with an extreme efficacy. They usually exhibit a very high specificity, reacting on one particular chemical compound or even on one given bond within the molecule [Broze 1999, Aehle 2004]. Detergent enzymes are not so specific. The most widely used detergent enzymes are hydrolases which catalyze the hydrolysis of a chemical bond. There are four types of hydrolases currently being used in liquid laundry detergents: protease, lipase, amylase and [Broze 1999, Aehle 2004]. support the removal of many soils commonly encountered by the consumer such as food stains, blood and grass. These enzymes catalyze the hydrolysis of the peptide bond found in proteins resulting in the formation of smaller and more soluble polypeptides and amino acids [Wolff et al. 1996, Subba et al. 2009, Singh et al. 2012, Zhang et al. 2014]. Amylase enzymes work on food stains of the starchy variety, like rice, sauce or gravy. These enzymes catalyze the hydrolysis of 1-4 glucosidic bonds in starch [Kravetz and Guin 1985, Hoshino and Tanaka 2003, Hoshino, Tanaka and Kanda 2006]. Lipase enzymes target the oily, greasy stains that are some of the most difficult stains to remove. Lipases catalyze the hydrolysis of mostly the C1 and C3 bonds in the triglyceride molecule, yielding free fatty acids and diglyceride [Varanasi et al. 2001, Bora 2014]. are capable of degrading the structure of damaged cellulose fibrils which exist mostly at the surface of cotton fiber s after multicycle washing and using. Cellulases cleave β -1,4-

9 glucosidic bonds incellulose and operate directly on the natural cotton fibers. Cellulases bring diverse benefits: fabric softening, color brightening, antipilling, soil-release properties and antiredeposition [Calvimontes, Stamm and Dutschk 2009, Calvimontes, Lant and Dutschk 2011]. The aim of this study was to determine the effect of various enzymes on the performance of liquid laundry detergents. In the paper samples of liquid laundry detergent containing selected hydrolases (lipase, amylase and protease) were prepared. Tests of the performance of liquid laundry detergents: viscosity, foaming properties and washing properties were conducted. The studies were carried out at three different temperatures: 20, 30 and 40° C. For the sake of comparison, the same tests were also performed for a commercially available product.

1. MATERIAL AND METHODS

The study examined liquid laundry detergents containing three enzymes: protease, amylase and lipase. The formulation of the liquid laundry detergent tested is specified in Table 1. For the purpose of comparison, an enzyme-free laundry detergent (Base) and a commercial product (Com) were also tested. The composition of the commercial product, based on the m anufacturer’s data, includes 5-15% anionic surfactants, <5% nonionic surfactants, phosphonates, soap, enzymes, fragrance.

Viscosity measurement

Dynamic viscosity measurements were performed with Brookfield DV-III rotational viscometer. Viscosity is measured with a rotating measuring tip called the spindle, which is immersed in the test fluid. Testing was performed at a temperature of 20 °C, with the spindle rotating at 10 rpm.

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Table 1. Formulation of liquid laundry detergent tested

Composition [ wt. % ] INCI Name Base P A L MixS Mix0

Laureth -7 10 -

Laureth -3 3 -

Sodium Laureth Sulfate 7 -

Propylene Glycol 2

Sodium Citrate 1

Protease - 0.5 - - 0.5 0.5

Amylase - - 0.5 - 0.5 0.5

Lipase - - - 0.5 0.5 0.5

Aqua to 100 Source: Authors own study

Foaming properties measurement

The foaming properties were determined using a method set out in the Polish standard [Polish Standard – foaming properties]. The method involved a measurement of the volume of foam produced by a free flow of the gel laundry detergent solution from a distributor onto the surface of the same solution inside a graduated cylinder. Measurements of volume were performed after 30 s, 1 min and 10 min. The concentration of the test solutions was 1 wt%. Based on measurements, two parameters were determined: - foaming ability, FA [cm 3] – volume of foam produced after 30 s. - foam stability, FS [%]:

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V FS = 10 4100 []% V 1 where: V10 – volume of foam measured after 10 min [cm 3], V1 – volume of foam measured after 1 min [cm 3].

Washing properties measurement

The washing properties were determined on the basis of methodology set out in the Polish standard [Polish Standard – washing properties]. The method involved washing of pieces of soiled test fabric in the test washing agent in strictly defined conditions. Pieces of cotton fabric were stained with, previously mixed, three types of soils: tannic, fat and protein. The fabric pieces were dried overnight in the open air. Fabrics prepared in this way were washed separately in the liquid laundry detergent tested. The concentration of the test liquid laundry detergent was 1 wt %. After washing, the pieces of fabric were rinsed and ironed, and their degree of whiteness was assessed. Based on tests, the following parameters were determined: - washing ability, WA [%]: X - B WA = 4100 []% A- B where: X – average degree of whiteness of soiled fabric after washing, B – average degree of whiteness of soiled fabric before washing, A – average degree of whiteness of unsoiled (control) fabric.

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3. RESULTS AND DISCUSSION

Viscosity of liquid laundry detergents is shown in Figure 1. The viscosity of the detergents tested ranged between 900-995 mPas. There was a slight increase in the viscosity of liquids containing the enzyme tested, but the difference was within the limit of error. It can therefore be stated that the surfactants system has stronger impact on the fluid viscosity and consistency than the addition of enzymes. Viscosity of the commercial product (Com) was equal to 650 mPas and was significantly lower than viscosity of other liquid detergents.

Figure 1. Dynamic viscosity of liquid laundry detergents tested. Source: Authors own study

Figure 2 shows foaming ability (diamonds) and foam stability (squares) of liquid detergents tested. All the tested detergents were characterized by a high foaming ability (320-330 cm 3) beyond commercial product for which this parameter was much lower: 210 cm 3. The foaming stability for the detergent without enzymes (Base) and detergen ts containing protease

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(P) and amylase (A) was comparable and its value was within the range 90-93 %. The addition of lipase resulted in a decrease of foam stability o 81 % for detergent containing only lipase (L) and detergent containing all three enzymes (MixS). Foam stability for the commercial product was the lowest – equal to 60 %.

Figure 2. Foaming ability (dark gray diamonds) and foam stability (light gray squares) of liquid laundry detergents tested. Source: Authors own study

The washing ability of the detergent tested is shown in Figure 3. The pieces of soiled fabric were washed separately by solutions of various liquid laundry detergents: detergent without enzymes (Base), detergents containing only one enzyme – protease (P), lipase (L) and amylase (A), detergent containing mixed three enzymes (MixS), detergent containing mix three enzymes but without any surfactant (Mix0) and commercial detergent (Com). The washing process was carried out at three different temperatures 20°C, 30°C and 40°C for 60 min.

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Figure 3. Washing ability of liquid laundry detergents tested in various temperature: 20°C, 30°C and 40°C . Source: Authors own study

Even the addition of a single enzyme to the surfactant system has a significant impact on the washing ability. This is particularly evident for addition of protease and lipase at 20°C. Amylase has smaller impact on the washing ability. Maximum efficiency of the stain removal was observed for Mix S, when the mix of the three enzymes was combined with the detergent system. In this case, the synergy effect between enzymes and between enzymes and surfactants is very important. [Kravetz and Guin 1985, Wolffet et al. 1996, Hoshino and Tanaka 2003, Hoshino, Tanaka and Kanda 2006, Subba et al. 2009, Singh et al. 2012, Zhang et al. 2014]. The minimal washing ability was observed for the liquid containing enzymes but without any surfactants (Mix0). This result may indicate that without a surfactant system the enzymes were destabilized and deactivated [Maaseand van Tilburg 1983, Kravetz and Guin 1985, Hoshino and Tanaka 2003, Hoshino, Tanaka and Kanda 2006, Zhang et al. 2014].

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The temperature of washing has a significant effect on the washing ability of the liquid detergent without enzymes (Base). For liquid with enzymes (P, A, L and MixS) the maximal washing ability was observed at 30 °C and increasing temperature to 40°C did not affect further growth of this parameter.

4. CONCLUSIONS

The study investigated the effect of three enzymes (protease, amylase and lipase) on performance of liquid laundry detergents. Various detergents were tested: without enzymes (Base), containing only one enzyme – protease (P), lipase (L) and amylase (A), containing mixed three enzymes (MixS), containing mixed three enzymes but without any surfactant (Mix0) and commercial detergent (Com). Tests of dynamic viscosity, foaming properties and washing properties were conducted. The washing process was carried out at three different temperatures 20°C, 30°C and 40° C. Based on the tests, the following findings were made: • the addition of the enzyme did not affect the change in viscosity of the liquid laundry detergent tested, in this case the consistency of the fluid detergents was primarily dependent on the surfactant system; • foaming ability did not depend on the addition of the enzyme; • foam stability was very high for detergents without lipase, the addition of this enzyme caused reduction of foam stability; • temperature of washing had a significant effect on the washing ability of the liquid detergent without enzymes while for liquid with enzymes maximum washing ability was observed at 30°C. Increasing temperature to 40°C did not affect further growth of this parameter.

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REFERENCES

Aehle W. 2004. Enzymes in Industry , Wiley-VCH Verlag GmbH, Weinheim. Bertleff W., Neumann P., Baur R., Kiessling D. 1998. Aspects of Polymer Use in Detergents , Journal of Surfactants and Detergents, vol. 1, issue 3, pp. 419-424. Bora L. 2014. Purification and Characterization of Highly Alkaline Lipase from Bacillus licheniformis MTCC 2465: and Study of Its Detergent Compatibility and Applicability , Journal of Surfactants and Detergents, 17, pp. 889–898. Broze G. 1999 . Handbook of Detergents , Marcel Dekker, Inc., New York. Calvimontes A., Lant N.J., Dutschk V. 2011. Cooperative Action of Cellulase Enzyme and Carboxymethyl Cellulose on Cotton Fabric Cleanability from a Topo- graphical Standpoint , Journal of Surfactants and Detergents, vol. 14, pp. 307–316. Calvimontes A., Stamm M., Dutschk V. 2009. Effect of Cellulase Enzyme on Cellulose Nano-topography , Tenside Surfactants Detergents, vol. 46, pp. 368–372. Hoshino E., Tanaka E. 2003. Enhancement of Enzymatic Catalysis of Bacillus amyloliquefaciens α -amylase by Nonionic Surfactant Micelles , Journal of Surfactants and Detergents, vol. 6, issue 4, pp. 299-303. Hoshino E., Tanaka E., Kanda T. 2006. Effects of a Nonionic Surfactant on the Behavior of Bacillus amyloliquefaciens a-amylase in the Hydrolysis of Malto-oligosaccharide , Journal of Surfactants and Detergents, vol. 9 issue 1, pp. 63-68. Kravetz, L., Guin K.F. 1985. Effect of Surfactant Structure on Stability of Enzymes Formulated into Laundry Liquids , Journal of American Oil Chemical Society vol. 62, pp. 943-949. Lai KY. 1997. Liquid Detergents , Marcel Dekker, Inc., New York. Maase F., van Tilburg R. 1983. The Benefit of Detergent Enzymes under Changing Washing Conditions , Journal of American Oil Chemical Society, vol. 60, pp. 1672–1675. Mahrholz T., Klein J., Klein T. 2004. New Poly(sodium carboxylate)s Based on Saccharides (II) Cobuilder Performance of Ionic Allyl Glycosidepolymers

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as Substitutes of Standard Polycarboxylates , Journal of Macromolecular Science, vol. 41, pp. 165-179. Olsen H., S., Falholt P. 1998. The Role of Enzymes in Modern Detergency, Journal of Surfactants and Detergents, vol. 1, issue 4, pp. 555-567. Polish Standard – Foaming Properties , PN-74/C-04801. Polish Standard – Washing Properties , PN-93/C-04810/01. Singh S.K., Singh S.K, Tripathi V.R., Garg S.K. 2012. Purification, Characterization and Secondary Structure Elucidation of a Detergent Stable, Halotolerant, Thermoalkaline Protease from Bacillus cereus SIU1 , Process Biochemistry, vol. 47, pp. 1479-1487. Smulders E. 2002. Laundry Detergents , Wiley-VCH Verlag GmbH, Weinheim. Subba R Ch., Satish T, Ravichandra P, Prakasham R.S. 2009. Characterization of Thermo- and Detergent Stable Serine Protease from Isolated Bacillus circulans and Evaluation of Eco-friendly Applications , Process Biochemistry, vol. 44, pp. 262–268. Tadros T.F. 2005. Applied Surfactants , Wiley-VCH Verlag GmbH, Weinheim. Varanasi A., Obendorf S.K., Pedersen L.S., Mejldal R. 2001. Lipid Distribution on Textiles in Relation to Washing with Lipases, Journal of Surfactants and Detergents, vol. 4, issue 2, pp. 135-146. Wolff A. M., Showell M. S., Venegal G. M., Barnett B.L., Wertz W.C. 1996. Laundry Performance of Subtilisin Protease. In: Bott R, Betzel C, editors. Subtilisin enzymes: practical protein engineering. New York: Plenum Press, pp. 113-120. Yangxin Y., Jin Z., Bayly A. 2008 . Development of Surfactants and Builders in Detergent Formulations, Chinese Journal of Chemical Engineering, vol. 16, issue 4, pp. 517-527. Zhang J., Zhang Y., Li W., Li X., Lian X. 2014. Optimizing Detergent Formulation with Enzymes , Journal of Surfactants and Detergents, vol. 17, pp. 1059-1067.

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STRESZCZENIE

W artykule badano wpływ stężenia oraz rodzaju wybranych enzymów na właściwości fizykochemiczne i użytkowe płynnych środków piorących. Enzymy są katalizatorami procesów biologi cznych i biochemicznych. Podobnie jak inne katalizatory enzymy przyspieszają reakcje obniżając ich energię aktywacji. Najczęściej stosowane w środkach piorących enzymy to hydrolazy, które pomagają w usunięciu zanieczyszczeń proteinowych, tłuszczowych oraz węglowodanowych. Szczególnie w przypadkach, gdy zanieczyszczenia te są słabo rozpuszczalne w wodzie. Rozpuszczalne w wodzie zanieczyszczenia są dosyć dobrze usuwane przez roztwór samego związku powierzchniowo czynnego, który zwilża powierzchnię plamy, od rywa ją od tkaniny i wprowadza do roztworu. Mechanizm takiego działania jest czysto fizyczny. W przypadku enzymów mechanizm usuwania zanieczyszczenia jest typowo chemiczny. Duże, nierozpuszczalne w wodzie cząsteczki są dzielone na mniejsze, rozpuszczalne w wodzie i łatwiejsze do usunięcia przez związki powierzchniowo czynne. Celem badań było określenie wpływu rodzaju enzymu na właściwości użytkowe i fizykochemiczne płynnych środków piorących. Badano trzy rodzaje enzymów: proteazę, lipazę oraz amylazę w stężeniu 0,5 % wag. Na podstawie opracowanej receptury sporządzono próbki płynów do prania. Dla porównania badano również płyn handlowy oraz środek zawierający enzymy, ale bez surfaktantów. Badano wpływ enzymu na lepkość, właściwości pianotwórcze oraz na zdolność wyprania. Badania zdolności wyprania wykonywano w trzech temperaturach: 20°C, 30°C and 40°C. Przeprowadzone badania wykazały, że dodatek badanych enzymów nie ma większego wpływu na lepkość oraz zdolność pianotwórczą płynnych środków piorących. Najwi ększy wpływ enzymów odnotowano na właściwości piorące. Zastosowanie enzymów pozwoliło na usunięcie większości zabrudzeń nawet w temp. 20°C. Podczas prowadzonych badań zaobserwowano efekt synergii między enzymami oraz związkami powierzchniowo czynnymi.

Sło wa kluczowe: płynne środki piorące, enzymy, hydrolazy, zdolność wyprania, właściwości pianotwórcze

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