Washing Performance Research Articles

Coproduction of protease and mannanase from Bacillus nealsonii PN-11 in solid state fermentation and their combined application as detergent additives

Bacillus nealsonii PN-11 produces thermo-alkalistable mannanase and protease active in wide temperature and pH range. Optimization of coproduction of protease and mannanase from this strain and application of cocktail of these enzymes as detergent additives were studied. On optimization mannanase yield of 834Ug−1 (11.12 fold increase) and protease yield of 70Ug−1 (4.7 fold increase) could be obtained in a single fermentation. Purification and characterization of mannanase have been done earlier and protease was done during this study and has a molecular mass of 48kDa. pH and temperature optima for protease were 10.0 and 65°C respectively. It was completely stable at 60°C for 3h and retained >80% of activity at pH 11.0 for 1h. Both the enzymes were compatible with detergents individually and in a combination. The wash performance of the detergent on different type of stains improved when protease or mannanase were used individually. However destaining was more efficient when a combination of mannanase and protease was used.

1460P - Robotic anticancer drug compounding assist system for the preparation of injectable antineoplastic drugs

Background: Many antineoplastic drugs are known to be mutagenic or teratogenic. Medical personnel handling antineoplastic drugs are at a high risk of occupational exposure. Therefore, in collaboration with Yaskawa Electric Corporation and Nikka Micron Co., Ltd, we developed the Cancer Drug Compounding Assist System (CDCAS). The CDCAS is an automated robotic system designed to efficiently facilitate the accurate preparation of drugs based on dose. In this study, we evaluated the CDCAS for accuracy, site contamination, and washing performance in the preparation of antineoplastic drugs. Methods: 5-Fluorouracil (5-FU; 600, 800, or 1200 mg) was added to 100 mL of saline; 5 samples of each formulation were prepared. The weight of the mixed drugs prepared using the CDCAS was compared to those prepared by a pharmacist, and the accuracy of each preparation was calculated in terms of percentage relative error. The acceptable variance was set at ± 5%. To test for contamination, cyclophosphamide (800 mg) was continuously added to 50 bags of 100 mL saline solution. Then, 25 locations inside the isolator were identified for measurement. Cyclophosphamide was collected from those sites by using a sampling sheet method. Twenty of those samples revealed adherence of 5-FU (300 µL) to the infusion bag surface. Ozonated water was used to wash 5-FU from the surface of the infusion bags. After the washing process, any 5-FU remaining on the infusion bag surface was recovered via a wiping method. Results: The average weight error ratio for the CDCAS and the pharmacist was −0.62% and 2.69%, respectively. Contamination of cyclophosphamide was confirmed at eight sites. Pollution of 5-FU was confirmed for two samples, and the removal rate was ≥ 99.9%. Conclusions: Our study demonstrated that the CDCAS’s preparation accuracy and cleaning performance are within acceptable limits. Thus, the CDCAS could be used to potentially reduce occupational exposure to antineoplastic drugs. Legal entity responsible for the study: Satohiro Masuda Funding: None Disclosure: All authors have declared no conflicts of interest.

What is the Hand Washing Performance in Foreign Domestic Helpers in Hong Kong?

BACKGROUND: There are over 312,000 foreign domestic helpers (FDHs) in Hong Kong. They are foreigners who provide full-time domestic services to serve the local households. Commonly, they take care babies, children and elders. Also, they prepare food and handle garbage. Their correct performance in hand washing is essential in reducing the spread of infections in household setting. The objective of this study was to assess the hand washing performance of FDHs in Hong Kong.

Stabilization of a Lipolytic Enzyme for Commercial Application

Thermomyces lanouginosa lipase has been used to develop improved methods for carrier-free immobilization, the Cross-Linked Enzyme Aggregates (CLEAs), for its application in detergent products. An activator step has been introduced to the CLEAs preparation process with the addition of Tween 80 as activator molecule, in order to obtain a higher number of the individual lipase molecules in the ”open lid” conformation prior to the cross-linking step. A terminator step has been introduced to quench the cross-linking reaction at an optimal time by treatment with an amine buffer in order to obtain smaller and more homogenous cross-linked particles. This improved immobilization method has been compared to a commercially available enzyme and has been shown to be made up of smaller and more homogenous particles with an average diameter of 1.85 ± 0.28 µm which are 129.7% more active than the free enzyme. The CLEAs produced show improved features for commercial applications such as an improved wash performance comparable with the free enzyme, improved stability to proteolysis and a higher activity after long-term storage.

Removal of heavy metals from polluted soil using the citric acid fermentation broth: a promising washing agent

The citric acid fermentation broth was prepared and it was employed to washing remediation of heavy metal-polluted soil. A well-defined washing effect was obtained, the removal percentages using citric acid fermentation broth are that 48.2% for Pb, 30.6% for Cu, 43.7% for Cr, and 58.4% for Cd and higher than that using citric acid solution. The kinetics of heavy metals desorption can be described by the double constant equation and Elovich equation and is a heterogeneous diffusion process. The speciation analysis shows that the citric acid fermentation broth can effectively reduce bioavailability and environmental risk of heavy metals. Spectroscopy characteristics analysis suggests that the washing method has only a small effect on the mineral composition and does not destroy the framework of soil system. Therefore, the citric acid fermentation broth is a promising washing agent and possesses a potential practical application value in the field of remediation of soils with a good washing performance.

Analysis of Aerosol Composition and Assessment of Tunnel Washing Performance within a Mass Rapid Transit System in Taiwan

ABSTRACTThe metro system is the main mode of transportation in Taipei City. The air quality of metro stations is crucial for passengers. This study investigated particle size distribution and its elemental composition and assessed tunnel washing performance in the Taipei Rapid Transit System (TRTS). A 24-hour particle sampling process was performed in the tunnels, platforms, and entrances and exits to measure particulate matter (PM)2.5 and PM10 concentrations in an underground metro station and to analyze PM metal components. PM10 and PM2.5 concentrations decreased sequentially from the tunnels to the platforms and then to the entrances and exits to ambient environment in the metro station. The main metal components of suspended particulates in the TRTS mainly included iron, barium, copper, manganese, magnesium, aluminum, chromium, zinc, nickel, and lead. The total PM10 and PM2.5 metal proportions were 33.9%–24.7% and 32.9%–22.8%, respectively. Furthermore, the effectiveness of tunnel washing in reducing the PM concentration was investigated. Monitoring results showed an increase in PM10 and PM2.5 concentrations after tunnel washing on the first day. The PM concentration started to decrease from the second day. Furthermore, 3.5 months after tunnel washing, the PM10 concentration decreased by 45.9%, and 2 months after tunnel washing, the PM2.5 concentration decreased by 71.3%. The mechanism of the continuous reduction in the PM10 concentration after cleaning is probably related to the porous material of tunnel walls, which may provide a deposition sink for aerosol particles, as well as the filter effect of the air conditioning system. This is the first study to use full-section tunnel washing to reduce PM exposure at mass rapid transit (MRT) stations. Although full-section tunnel washing reduced the PM concentration in the metro station, accessorial technology, such as the air conditioning system or platform design, may help in reducing the exposure of MRT passengers.

Strain improvement studies on Microbacterium foliorum GA2 for production of α-amylase in solid state fermentation: Biochemical characteristics and wash performance analysis at low temperatures.

Microbacterium foliorum GA2, an alkali-tolerant bacterium, was randomly mutated using UV radiation and sodium azide to obtain a mutant with a higher cold-active extracellular amylolytic activity. A mutant, designated as MFSD20, was selected owing to its higher amylase activity at 20°C. Under optimized conditions, amylase production was achieved best with raw banana peels (5000 units) in solid-state fermentation (SSF). The enzyme was purified by salt precipitation and chromatographic methods and afterwards characterized biochemically. The purified enzyme showed maximal activity at temperatures between 15-25°C and at pH 8.0. Interestingly, this mutant biocatalyst (MFSD20) displays higher catalytic activity under conditions of low temperature (4°C) and high pH (10.0), in the presence of SDS (0.1 and 1%), and exhibited 85% and 50% requirement of divalent metallic ions Ca2+ and Mg2+, respectively. This mutant enzyme extract in combination with "Wheel detergent" was highly effective in the removal of tomato sauce and chocolate stains from white cotton fabric was demonstrated by ~50% additional reflectance compared with detergent alone, in a wash performance analysis at 20 ± 2°C. The features shown by mutant M. foliorum GA2 make it a promising candidate for industrial applications involving starch degradation at low temperatures.

Impact of dissolved matter in the oxygen delignification stage

The presence of dissolved matter in the pulp suspension in an oxygen (O2) delignification stage, consisting mainly of dissolved lignin, is normally considered to negatively affect the delignification rate due to the competing reactions between the fiber bound lignin and the lignin dissolved in the filtrate. Recirculated oxidized filtrate from the post-O2 washing is usually considered to be less harmful to the delignification efficiency than unoxidized dissolved matter originating from the cooking stage. To develop a better understanding of the mechanisms of the dissolved matter’s reactions and impact on the O2 stage performance, laboratory oxygen delignification experiments with varying levels of unoxidized and oxidized dissolved matter were conducted. The results showed that unoxidized dissolved matter had a negative impact on the delignification in the O2 stage, whereas oxidized dissolved matter actually had a positive effect. The delignification efficiency of the laboratory experiments thus depends on both the amount of dissolved matter and its origin. The pulp viscosity decreased with increasing dissolved matter content irrespective of its origin but at higher COD levels; however, the viscosity drop was larger for the unoxidized dissolved matter. In terms of selectivity, the oxidized filtrate had a similar impact as additional NaOH charge. Both types of filtrates consumed hydroxide and the final pH decreased with increasing dissolved matter content. The final pH was significantly lower in the unoxidized filtrate experiments at higher COD levels, indicating a high reactivity between the unoxidized dissolved matter and the oxygen in the reactor. Based on the results, further understanding is achieved about the relation between pre-O2 washing performance and process configuration in an actual mill case, as well as the impact of dissolved matter on delignification. The importance of efficient removal of harmful unoxidized dissolved matter is verified, but the results also suggest that the oxidized dissolved matter that is recirculated from post-O2 washing actually has a significant positive impact on the delignification and is not just a potential problem in case of carryover to the bleach plant. Subsequently, pulp washing efficiency is critical both pre- and post-O2.

Optimization, Purification, and Starch Stain Wash Application of Two New α-Amylases Extracted from Leaves and Stems of Pergularia tomentosa.

A continuous research is attempted to fulfil the highest industrial demands of natural amylases presenting special properties. New α-amylases extracted from stems and leaves of Pergularia tomentosa, which is widespread and growing spontaneously in Tunisia, were studied by the means of their activities optimization and purification. Some similarities were recorded for the two identified enzymes: (i) the highest amylase activity showed a promoted thermal stability at 50°C; (ii) the starch substrate at 1% enhanced the enzyme activity; (iii) the two α-amylases seem to be calcium-independent; (iv) Zn2+, Cu2+, and Ag2+ were considered as important inhibitors of the enzyme activity. Following the increased gradient of elution on Mono Q-Sepharose column, an increase in the specific activity of 11.82-fold and 10.92-fold was recorded, respectively, for leaves and stems with the presence of different peaks on the purification profiles. Pergularia amylases activities were stable and compatible with the tested commercial detergents. The combination of plant amylase and detergent allowed us to enhance the wash performance with an increase of 35.24 and 42.56%, respectively, for stems and leaves amylases. Characterized amylases were reported to have a promoted potential for their implication notably in detergent industry as well as biotechnological sector.

Surfactant- and oxidant-stable alkaline proteases from Bacillus invictae: Characterization and potential applications in chitin extraction and as a detergent additive

A newly alkaline proteases producing strain was isolated from sea water. The strain was identified as Bacillus invictae on the basis of biochemical characteristics and 16S rRNA sequence analysis. The crude protease activity showed an optimal activity at approximately 60°C and in wide pH interval ranging from 9.0 to 11.0. At least six clear caseinolytic protease bands were observed in a zymogram. Phenylmethylsulfonyl fluoride (PMSF), a serine-protease inhibitor, was found to inhibit completely the protease activity. The crude alkaline proteases showed high stability toward solid and liquid detergents. Furthermore, wash performance analysis revealed that the crude enzyme could effectively remove blood stain when added to commercial detergent. In addition, the crude proteases were found to be effective in the deproteinization of shrimp shell waste. The percent of protein removal after 3h of hydrolysis at 50°C with an E/S ratio of 10U/mg of protein or after fermentation by the strain were about 76% and 82%, respectively. Thus, the results of the present study showed that the crude proteases of B. invectae could be effectively used in several industrial applications, as an eco-friendly agent.

Effects of Operation Variables and Electro-kinetic Field on Soil Washing of Arsenic and Cesium with Potassium Phosphate

The operation variables and electro-kinetic field (EKF) were investigated to enhance the remediation of arsenic (As)- and cesium (Cs)-contaminated soils with soil washing. Extractant types, concentrations, liquid/solid (L/S) ratios, solution pH values, washing temperatures, and agitation modes were important criteria to determine the efficiency of soil washing. The KH2PO4 was proved to be a suitable alternative to Na2EDTA in extracting As and Cs from contaminated soils. A 2-h washing with KH2PO4 at concentration of 0.01 M and L/S ratio of 20 mL g−1 showed the most efficient washing performance. In addition, the lower solution pH, higher temperature, and ultrasound also favored soil washing of As and Cs with KH2PO4. The EKF greatly enhanced metals extraction with soil washing. It offered acidic soil environment around the anode areas for the release of soluble Cs from its soil solid-phase components before soil washing. Moreover, the alkalization around the cathode areas also benefited the desorption of stable As since labile As were mainly presented in anionic forms. The effect of CA for neutralizing OH− was proved to be limited, while the reversed subsequent EKF process effectively alleviated Cs precipitation generated during the initial EKF process. It also effectively restored soil pH altered by the initial EKF. The overall EKF (4 V cm−1) enhanced removal efficiency of As and Cs with soil washing from the anode area was 37 and 31%, respectively. Higher removal of As (52%) was obtained in the cathode area. Moreover, the reversed EKF resulted in another 28% removal of Cs in the initial cathode area which showed the capacity of EKF on continuous soil metal remediation.

Biochemical properties and evaluation of washing performance in commercial detergent compatibility of two collagenolytic serine peptidases secreted by Aspergillus fischeri and Penicillium citrinum

ABSTRACTFilamentous fungi secrete diverse peptidases with different biochemical properties, which is of considerable importance for application in various commercial sectors. In this study, we describe the isolation of two fungal species collected from the soil of decayed organic matter: Aspergillus fischeri and Penicillium citrinum. In a submerged bioprocess, we observed better peptidase production with the fungus P. citrinum, which reached a peak production at 168 h with 760 U/mL, in comparison with the fungus A. fischeri, which reached a peak production at 72 h with 460 U/mL. In both situations, the fermentative medium contained 0.5% crushed feathers as a source of nitrogen. On performing biochemical characterization, we detected two alkaline serine peptidases: The one secreted by P. citrinum had optimal activity at pH 7.0 and at 45°C, while the one secreted by A. fischeri had optimal activity in pH 6.5–8 and at 55–60°C. Metallic ions were effective in modulating these peptidases; in particular, Cu2+ promoted negative modulation of both peptidases. The peptidases were stable and functional under conditions of nonionic surfactants, temperatures up to 45°C for 1 h, and incubation over a wide pH range. In addition, it was observed that both peptidases had the capacity to hydrolyze collagen and performed well in removing an egg protein stain when supplemented into a commercial powder detergent; this was especially true for the peptidase from P. citrinum.

Characterization of a novel protease from Aeribacillus pallidus strain VP3 with potential biotechnological interest

The present study investigates the purification and physico-chemical characterization of an extracellular protease from the Aeribacillus pallidus strain VP3 previously isolated from a geothermal oil-field (Sfax, Tunisia). The maximum protease activity recorded after 22h of incubation at 45°C was 3000U/ml. Pure enzyme, designated as SPVP, was obtained after ammonium sulfate fractionation (40–60%)-dialysis followed by heat-treatment (70°C for 30min) and UNO Q-6 FPLC anion-exchange chromatography. The purified enzyme is a monomer of molecular mass about 29kDa. The sequence of the 25 NH2-terminal residues of SPVP showed a high homology with those of Bacillus proteases. The almost complete inhibition by PMSF and DIFP confirmed that SPVP is a member of serine protease family. Its optima of pH and temperature were pH 10 and 60°C, respectively. Its half-life times at 70 and 80°C were 8 and 4h, respectively. Its catalytic efficiency was higher than those of SAPCG, Alcalase Ultra 2.5L, and Thermolysin type X. SPVP exhibited excellent stability to detergents and wash performance analysis revealed that it could remove blood-stains effectively and high resistance against organic solvents. These properties make SPVP a potential candidate for applications in detergent formulations and non-aqueous peptide biocatalysis.

Differentiated Evaluation of Washing Performance in Washing Machines of Test Stain Strips as a Function of Temperature, Washing Duration and Load Size

Abstract Since the washing performance of household washing machines must comply with certain limit values, like the ecodesign requirements in Europe, the method of washing performance evaluation is crucial. Today, the washing performance is defined as an overall washing performance in IEC 60456:2010, constituting an calculation of the average sum of reflectance values of five different stain monitors. As a result, the different washing characteristics of each individual stain are totally neglected. This study investigates how the washing cycle affects the individual stains, when washing temperature, washing time and load size are varied systematically. The results show individual stains contribute differently to the overall washing performance. For a proper assessment of the washing performance, the individual stains’ contributions to the overall washing performance are required to be considered. A supplement of temperature sensitive stain monitors is suggested. E.g., as tea has a crucial contribution at higher temperature, this stain should have a higher influence in washing performance assessment when good bleaching or hygiene performance is requested.

New Evaluation Method of Cleaning Performance for Washing Machines

Abstract Several different approaches are commonly used to obtain information about the performance of laundry systems, e.g. washing machines. The evaluation of washing performance with soiled test fabrics is commonly done by measuring the reflectance of the washed test specimen. The absolute reflectance readings may be used if the results are only compared within a series of tests using the same batches of test materials for all runs. The inevitable uncertainty of any test results may be reduced if the results can be expressed as ratios compared to the performance of well-known or well-established reference systems tested in parallel. This approach is defined in IEC 60456:2010 and followed globally for assessing the performance of washing machines. With the current evaluation method the calculation of the overall wash performance test result cannot be adjusted to adequately reflect the characteristics of different wash programmes designed for different purposes – or different machine technology and global regions. It is therefore the task of this paper to develop an evaluation method for assessing the cleaning performance of washing machines which is scientifically sound and statistically complete and more flexible in its application to different programmes and/or regions. A new cleaning evaluation method is suggested in this paper and applied to two sets of available data. The new cleaning evaluation method shows to have a number of apparent advantages over the method currently used. As a straightforward approach the stain specific evaluation ensures full usage of generated information including reference machine and batch values to allow calibrating the test result. The full statistical evaluation gives a more complete picture and allows partial results to reflect different aspects of system performance as well as weighting factors allow adjustment to specific requirements.

Understanding Interactions of Surfactants and Enzymes: Impact of Individual Surfactants on Stability and Wash Performance of Protease Enzyme in Detergents

Abstract Enzymes and surfactants are both essential ingredients that determine the performance of modern laundry detergents. We have conducted an investigation of the interaction of surfactants and enzymes under laundry detergent application conditions in order to understand the influence of individual ingredients and to optimize detergent performance. We can show that for a given protease enzyme, individual surfactants in a constant detergent matrix have a significant impact on relevant stability and performance parameter. While certain anionic surfactants like e.g. linear alkylbenzene sulfonate show strong protease inactivation, nonionic surfactants did only show slight inactivation over time. On the other hand, proteolytic performance of protease on test stains was most driven by fatty alcohol ether sulfate. Knowledge about the impact of individual surfactants on proteases will enable the best choice of ingredients for mixed surfactant systems with optimized enzyme performance and stability.

Textile Quality Depletion due to Household Machine Wash – Ways to Measure and Impacts of Wash Duration and Temperature on Textiles

Abstract Washing machines should not only deliver good removal of stains, but also take care of the garments. Mechanical action produced by the washing machine has a twofold impact: It supports the removal of stains, but it also influences the structure of the textiles negatively and is, therefore, critical to textile care. Most washing machines are currently assessed by consumer organisations and political regulations, such as energy labelling, just for their washing properties. However, a long programme may provide a good washing performance, but might also damage the textiles more than a shorter programme. Test specimens assessing the mechanical impact are well known and published, for example, IEC PAS 62473:2007, however, they are rarely used. Reasons may be poor knowledge about their effectiveness in assessing the mechanical action and their reaction to different washing conditions, for example, load size, temperature and duration of the washing programme. It was the task of this study to verify this relationship and confirm that the thread removal fabric, as specified in IEC PAS 62473:2007, adds additional information to the assessment of a washing process. As a result of a wide variation of washing parameters, it could be shown that this test fabric is almost independent of the washing temperature, but shows a clear correlation with the load size and the length of the washing process. The thread removal specimens add valuable additional information concerning a relevant parameter of the washing process.

Substrate kinetics of thiol activated hyperthermostable alkaline lipase of Bacillus sonorensis 4R and its application in bio-detergent formulation

Abstract The substrate kinetics of a hyperthermostable alkaline lipase from Bacillus sonorensis 4R (BSL) was studied and the enzyme was used to develop presoak formulation for removing oil stains at 37 °C and 80 °C. The purified BSL was thiol activated with 112.49% and 37.49% enhancement in presence of 5 mM thiourea and dithiothreitol (DTT) respectively. BSL displayed higher specificity for mustard oil and cotton seed oil cake than olive oil as a standard substrate. The maximal velocity (Vmax) and Michaelis constant (Km) values determined in presence of olive oil, mustard oil and cotton seed oil cake were 5.0, 7.14, 5.55 µM and 3.22, 2.5 and 2.22 µM/ml/min respectively. Effect of phenylmethylsulfonyl flouride (PMSF) and N-Bromosuccinimide (NBS) on BSL catalyzed hydrolysis of olive oil, mustard oil and cotton seed oil cake were studied in terms of changes in Vmax, Km, catalytic efficiency and substrate utilization capacity. BSL catalyzed improved hydrolysis of cotton seed oil cake in presence of thiourea and retained 100% stability in presence of non-polar solvents, surfactants and detergents. BSL (15 Eu/100 ml) was effective in removal of olive oil stains studied at three aging periods (0, 7 and 15 d) and two washing temperatures (37 °C and 80 °C). The BSL action during wash performance studies for all aging periods was demonstrated clearly by quantitated fatty acid release. BSL exhibited excellent olive oil removal capacity than buffer (pH 9.0) and Tide (1%). The combination of BSL and Tide proved best formulation for stain removal of olive oil soiled fabrics.

An Alkaline Protease from Bacillus pumilus MP 27: Functional Analysis of Its Binding Model toward Its Applications As Detergent Additive.

A proteolytic strain of Bacillus pumilus MP 27 was isolated from water samples of Southern ocean produced alkaline protease. Since protease production need expensive ingredients, an economically viable process was developed by using low cost carbon source, wheat straw, supplemented with peptone. This protease was active within temperature ranges 10–70°C at pH 9. This process was optimized by response surface methodology using a Box Bekhman design by Design Expert 7.0 software that increased the protease activity to 776.5 U/ml. Moreover, the enzyme was extremely stable at a broad range of temperature and pH retaining 69% of its activity at 50°C and 70% at pH 11. The enzyme exhibited excellent compatibility with surfactants and commercial detergents, showing 87% stability with triton X-100 and 100% stability with Tide commercial detergent. The results of the wash performance analysis demonstrated considerably good de-staining at 50 and 4°C with low supplementation (109 U/ml). Molecular modeling of the protease revealed the presence of serine proteases, subtilase family and serine active site and further docking supported the association of catalytic site with the various substrates. Certainly, such protease can be considered as a good detergent additive in detergent industry with a possibility to remove the stains effectively even in a cold wash.

Washing efficiency and fabric damage by beating and rubbing movements in comparison with a front-loading washer

The objective of this study was to evaluate washing performance by beating and rubbing movements that simulate traditional washing methods. By comparing washing performance between these washing methods and a front-loading washer, we examined the potential of the new washing technique and proposed an efficient washing system. In this study, the new rubbing movement, that mimics a washboard, shows low fabric damage with high washing efficiency. The rubbing movement provides high mechanical force, which allowed easy transfer between soil and the detergent solution on the fabric surface. Thus, efficient washing can be accomplished by rubbing movements which minimize fabric damage and achieve high washing efficiency. A beating movement that copies a laundry bat gave the lowest damage and washing performance, so may be used for delicate textiles. In addition, location changes through flexing enhanced washing efficiency and showed better performance than strong force in a fixed location.