Detergent Formulations Research Articles

Enzyme‐Compatible Dynamic Nanoreactors from Electrostatically Bridged Like‐Charged Surfactants and Polyelectrolytes

AbstractReported is an unanticipated mechanism of attractive electrostatic interactions of fully neutralized polyacrylic acid (PAA) with like‐charged surfactants. Amphiphilic polymer‐surfactant complexes with high interfacial activity and a solubilization capacity exceeding that of conventional micelles are formed by bridging with Ca2+ ions. Incorporation of a protease into such dynamic nanoreactors results in a synergistically enhanced cleaning performance because of the improved solubilization of poorly water‐soluble immobilized proteins. Competitive interfacial and intermolecular interactions on different time‐ and length‐scales have been resolved using colorimetric analysis, dynamic tensiometry, light scattering, and molecular dynamic simulations. The discovered bridging association mechanism suggests reengineering of surfactant/polymer/enzyme formulations of modern detergents and opens new opportunities in advancing labile delivery systems.

Laundry Detergent Compatibility of Papain Like Protease Purified From Piper Betel Leaves

Enzymes have wide applications in detergent industry from early 1900’s. Mostly, clothes are soiled by protein based grime. Most of the detergents have either amylase / protease. Various sources were scrutinized for potent protease activity and Betel leaves were selected, the enzyme was then isolated, purified to homogeneity by ammonium sulphate precipitation, DEAE-Cellulose and gel permeation chromatographic techniques. The enzyme was monomeric in nature with a molecular mass of 38kDa as determined by native PAGE and SDS-PAGE. The enzyme shows maximum activity at 60oC and pH 4.0. The Km and Vmax of the enzyme were 4x10-3M and 54µmol/min/mg respectively. The enzyme was categorically inhibited by PCMB and iodo-acetamide suggesting it to have papain like nature. The stability of the enzyme is assessed over the stretch of alkaline pH and temperature. This evaluation validates the stability of the enzyme and its use in detergent formulations. It was evident that after adding the enzyme preparation the stains (tea, chocolate, blood) were removed much better than that of the controls, which affirms that papain like enzyme from betel leaves, enhances detergent activity.

Enzyme-Polymer Conjugates to Enhance Enzyme Shelf Life in a Liquid Detergent Formulation.

Herein, the synthesis of enzyme-polymer conjugates is reported. Four different activated polymers (mPEG-aldehyde, mPEG-NHS, maltodextrin-aldehyde, carboxymethyl cellulose aldehyde) are conjugated to the surface of protease, α-amylase, and lipase using two different strategies (reductive amination and alkylation with NHS-activated acid). Although the chemical modification of the enzymes is accompanied by losses in enzyme activity (maximum loss 40%), the covalent attachment of polymers increases the thermal stability and the stability in a standard detergent formulation compared to the unmodified enzymes. The enzyme-polymer conjugates are characterized by asymmetrical-flow field-flow fractionation and differential scanning microcalorimetry. Furthermore, it is demonstrated that conjugated enzymes still show performance in a real washing process. Enzyme-polymer conjugates show a potential as a stabilizing system for enzymes in detergents.

Purification and characterization of a novel extracellular serine-protease with collagenolytic activity from Aspergillus tamarii URM4634

An extracellular serine-protease from Aspergillus tamarii URM4634 was purified and characterized. The possibility of using Aspergillus tamarii URM4634 protease in detergent formulations and collagenolytic activity was investigated. The protease demonstrated excellent stability at pH range 7.0–11.0, the optimum being at pH 9.0. The enzyme was stable at 40 °C for 180 min, enhanced by Mg++ and Ca++, but inhibited by Zn++, and strongly inhibited by phenylmethylsulfonyl fluoride (PMSF), suggested as serine-protease. The azocasein substrate result showed Km = 0.434 mg/mL and Vmax = 7.739 mg/mL/min. SDS-PAGE and azocasein zymography showed that the purified alkaline protease (2983.8 U/mg) had a molecular mass of 49.3 kDa. The enzyme was purified by column chromatography using Sephadex A50 resin. The proteolytic activity was activated by SDS (sodium dodecyl sulfate), Tween-80, Tween 20 and Triton-100. This study demonstrated that A. tamarii URM4634 protease has potent, stable and compatible collagenolytic activity to the desired level in local laundry detergent brands compared with similar enzymes produced by solid-state fermentation. This protease can thus be chosen as an option in both the food industry to tenderization meat and the detergent industry to washing process.

Purification and characterization of an organic solvent-tolerant and detergent-stable lipase from Haloferax mediterranei CNCMM 50101

The present study investigates the purification and biochemical characterization of an extracellular lipase (HML) from Haloarchaea Haloferax mediterranei strain ATS1, isolated from the Sebkha (Medea, Algeria). The pure protein was obtained with ammonium sulfate precipitation (40–70%)-dialysis and UNO Q-6 FPLC, and characterized biochemically. Matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that the purified enzyme was a monomer, with a molecular mass of 45,011.09 Da. It showed optimum lipase activity at pH 7 and 60 °C. HML showed a higher specific activity on triacylglycerols with long-chains fatty acids, indicating that HML is a true lipase. This enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggested its belonging to the serine lipase family. The Km and Vmax for HML toward olive oil were 1.01 mM and 1195 U/mg, respectively. Compared to Lipolase, HML displayed an elevated organic solvent tolerance, an outstanding stability to surfactants, oxidizing, and auxiliary agents, a considerable compatibility with various commercialized laundry detergents, and wash performance analysis revealed that it could remove oil-stains effectively. Overall, HML has a number of attractive properties that make it a potential promising candidate for the synthesis of non-aqueous peptides and detergent formulations.

Study on the potential of cold-active lipases from psychrotrophic fungi for detergent formulation.

Lipases from psychrotrophic fungal isolates BPF4 and BPF6 identified as Penicilium canesense and Pseudogymnoascus roseus respectively were characterized for their compatibility towards laundry detergent. BPF4 and BPF6 lipases showed maximum activity at pH 11 and 9 respectively and at 40 °C. The residual activities at 20 °C and 4 °C of BPF4 lipase were 35% and 20% and of BPF6 lipase were 70% and 20 °C respectively. Both the enzymes were stable at 4 °C, 20 °C and 40 °C for 2 h losing at the most 20% of activities. Both the enzymes were metalloenzymes with activity enhancement by nearly threefold by Ca2+. Contrary to BPF6 lipase, BPF4 enzyme was not stimulated by EDTA nor inhibited, rather stimulated by SDS and Triton X-100 by 125% and 330% respectively. Both the lipases showed minor to moderate inhibition by NaClO3 and H2O2, and exhibited nearly 90% residual activity after 1 h of incubation in selected detergent brands thus indicating potential for their inclusion in detergent formulation thereby facilitating cold-washing as a step towards mitigation of climate change.

Comparative interaction study of amylase and surfactants for potential detergent formulation

Enzymes have been widely used in modern detergents, however, few studies deal with enzymes dosage as well as its relationship with the other. Enzyme based detergents have been used for remodeling the cleaning efficiency of detergents for many years. Enzyme amylase finds its application in all the industrial processes for the hydrolysis of starch. Amylase is also known for improving detergent efficacy especially at lower temperatures and at lower pH levels. Presence of different surfactant also plays an important role in enhancing the detergent efficacy. So, this paper investigates the physico-chemical properties to obtain the critical micellar concentration (CMC), the thermodynamic parameters (ΔH°m, ΔG°m, ΔS°m) of anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and non-ionic surfactant TWEEN 20 in the presence of an enzyme Aspergillus oryzae originated α-amylase at varying temperatures for formulating a possible better combination of surfactant and amylase for making an eco-friendly detergent. Further surface tension studies, the kinetic studies (Km and Vmax values) have been carried out. Then the degradation studies have been performed to calculate the biological oxygen demand (BOD) to conduct a comparative analysis which would be helpful in potential detergent formulation and in analyzing their environmental impact as minimal the BOD, maximal the degradation of formulated detergent on dispose off.

Foaming and Cleaning Performance Comparison of Liquid Detergent Formulations using Mixtures of Anionic and Nonionic Surfactants

AbstractModern detergents are typically appreciated for their cleaning performance rather than foaming characteristics. The aim of the current study was to compare the foaming and cleaning abilities of liquid detergents, built from a combination of surfactants, to be applied for household laundry purpose. A total of eighteen different liquid detergent formulations containing mixtures of important anionic, nonionic surfactants, and other additives were prepared. The first set of nine new detergent formulations (S1) was prepared using the surfactants sodium lauryl sulfate (SLS), Tween-20 and Tween-80. Another set of nine new detergent formulations (S2) was prepared using surfactants SLS, Triton X-100 and alkyl polyglucoside (APG). The impact of water quality (RO, hypersaline or hard water) on the foam properties of the detergent formulation sets (S1 and S2) was systematically examined. The second set of detergent formulations (S2) showed a better performance in terms of foamability and foam stability, regardless of the water quality. Also, the surface tension of the detergent formulation set S2 was found to be lower and it showed a higher detergency for both cotton and woolen fabrics. The detergency of the formulation no S2.9 (in set S2) was the maximum amongst all the detergent formulations. The surface morphology of the cotton and woolen fabrics, washed with liquid detergent formulation no S2.9, displayed the removal of oily soil and grease from the surface of the fabrics, without affecting the quality of the fabrics.

The consistent differential expression of genetic pathways following exposure of an industrial Pseudomonas aeruginosa strain to preservatives and a laundry detergent formulation.

Pseudomonas aeruginosa is a common contaminant associated with product recalls in the home and personal care industry. Preservation systems are used to prevent spoilage and protect consumers, but greater knowledge is needed of preservative resistance mechanisms used by P. aeruginosa contaminants. We aimed to identify genetic pathways associated with preservative exposure by using an industrial P. aeruginosa strain and implementing RNA-Seq to understand gene expression changes in response to industry relevant conditions. The consistent differential expression of five genetic pathways during exposure to multiple industrial growth conditions associated with benzisothiazolone (BIT) and phenoxyethanol (POE) preservatives, and a laundry detergent (LD) formulation, was observed. A MexPQ-OpmE Resistance Nodulation Division efflux pump system was commonly upregulated in response to POE, a combination of BIT and POE, and LD together with BIT. In response to all industry conditions, a putative sialic acid transporter and isoprenoid biosynthesis gnyRDBHAL operon demonstrated consistent upregulation. Two operons phnBA and pqsEDCBA involved in Pseudomonas quinolone signaling production and quorum-sensing were also consistently downregulated during exposure to all the industry conditions. The ability to identify consistently differentially expressed genetic pathways in P. aeruginosa can inform the development of future targeted preservation systems that maintain product safety and minimise resistance development.

Thermodynamics of a Ca2+ dependent, highly thermostable and detergent compatible purified alkaline serine protease from Nocardiopsis xinjiangensis strain OM-6

Extracellular alkaline protease producing salt tolerant alkaliphilic actinobacteria, Nocardiopsis xinjiangensis strain OM-6 was isolated from Okha Madi (OM) site of coastal Gujarat, India. The purified protease was stable even at 70°C in 100mM Ca2+ with Kd=20×10−3 and t1/2=34min. The activation energies (E), enthalpy (∆H*) and entropy (∆S*) for protease deactivation were 29.35kJ/mol, 26.68kJ/mol and −186.22J/mol, respectively in 200mM Ca2+. The ∆G* for protease deactivation was 97.63kJ/mol at 50°C in 100mM Ca2+. OM-6 protease exhibited enhanced residual activities up to 103%, 70%, 144% and 119% with SDS, CTAB, Tween 80 and Triton X-100, respectively after 2h of incubation at 40°C. Interestingly, residual activity of OM-6 protease increased by 450% and 559% in 50mM H2O2 and 10mM β-mercaptoethanol respectively even after 2h of incubation. Moreover, protease retained 100% of its original activity with H2O2 and β-mercaptoethanol at highest concentration after 24h. The protease retained more than 60% of original activity with 1% w/v of each commercial detergent even after 2h at 40°C. These unique properties of protease make it an ideal choice for application in detergent formulations and enzymatic peptide synthesis.

Optimisation of preparation conditions for Ti nanowires and suitability as an antibacterial material.

Ultrafine titanium dioxide (TiO2) nanowires were synthesised using a hydrothermal method with different volumes of ethylene glycol (EG) and annealing temperatures. It shows that sodium titanate nanowires synthesised using 5 and 10 ml EG, which annealed at 400°C produced TiO2 nanowires that correspond to a photochemically active phase, which is anatase. The influences of annealing temperatures (400-600°C) on the morphological arrangement of TiO2 nanowires were evident in the field emission scanning electron microscopy. The annealing temperature of 500°C led to agglomeration, which formed a mixture of TiO2 nanoparticles and nanowires. High thermal stability of TiO2 nanowires revealed by thermogravimetric analysis and Fourier transform infrared spectroscopy spectrum showed the presence of the Ti-O-Ti vibrations as evidenced due to TiO2 lattices. An antibacterial study using TiO2 nanowires toward Escherichia coli and Klebsiella pneumoniae showed large zones of inhibition that indicated susceptibility of the microbe toward TiO2. Growth kinetic analysis shows that addition of TiO2 has reduced optical density (OD) suggesting an inhibition of the growth of bacteria. These results indicate TiO2 nanowires can be effectively used as an antimicrobial agent against gram-bacteria. The TiO2 nanowires could be exploited in the medical, packaging and detergent formulation industries and wastewater treatment.

A cold and organic solvent tolerant lipase produced by Antarctic strain Rhodotorula sp. Y-23.

Psychrotolerant yeast Rhodotorula sp. Y-23 was isolated from the sediment core sub-samples of Nella Lake, East Antarctica. Isolate was screened for lipase production using plate assay method followed by submerged fermentation. Production optimization revealed the maximum lipase production by using palmolein oil (5% v/v), pH 8.0 and inoculum size of 2.5% v/v at 15 °C. The potential inducers for lipase were 1% w/v of galactose and KNO3 , and MnCl2 (0.1% w/v). Final productions with optimized conditions gave 5.47-fold increase in lipase production. Dialyzed product gave a purification fold of 5.63 with specific activity of 26.83 U mg-1 and 15.67% yields. This lipase was more stable at pH 5.0 and -20 °C whereas more activity was found at pH 8.0 and 35 °C. Stability was more in 50 mM Fe3+ , EDTA-Na (20 mM), sodium deoxycholate (20 mM), H2 O2 (1% v/v), and almost all organic solvents (50% v/v). Tolerance capacity at wider range of pH and temperature with having lower Km value i.e., 0.08 mg ml-1 and higher Vmax 385.68 U mg-1 at 15 °C make the studied lipase useful for industrial applications. Besides this, the lipase was compatible with commercially available detergents, and its addition to them increases lipid degradation performances making it a potential candidate in detergent formulation.

The performance test of fatty acid methyl ester sulfonates and application in the dishwashing liquid detergent

ABSTRACTHydrolytic stability, foaming power and foam stability, calcium soap dispersing ability and stability in hard water of fatty acid methyl ester sulfonate (MES) were measured by potentiometric titration, Ross-Miles foam instrument, improved acid titration and turbidimetric test, respectively. The dishwashing detergent formulations containing MES were designed and stability and detergency of dishwashing detergents have been tested. The results showed that when storage temperature was 45°C, MES in pH 4.5 ∼ 9 was stable, disodium α-sulfonated fatty acid esters content increased at pH 10, hydrolysis rate was accelerated; foaming power of MES was lower than sodium linear alkyl benzene sulfonate (LAS) and the foam stability was equivalent to that of LAS; MES showed very excellent calcium soap dispersing ability, calcium soap dispersing amount of MES was 2.5 g calcium soap /1 g MES and LAS was 0.34 g /1 g LAS; differential stability of MES in hard water was , and LAS was ; the performance test results of dishwashing detergent products partially substituted LAS by MES can both meet the requirements of the Chinese national standard.

Promising Biosurfactant Produced by Cunninghamella echinulata UCP 1299 Using Renewable Resources and Its Application in Cotton Fabric Cleaning Process

A biosurfactant was produced from Cunninghamella echinulata using sustainable technology for cleaning and degreasing of cotton fabric impregnated with burned motor oil. The surface tension was 32.4 mN/m on a medium containing instant noodle waste (2%), corn steep liquor (2%), and postfrying oil (0.5%) with a carbon/nitrogen ratio of 30 : 1, yield of 6.0 g·L−1, emulsifier index of 81.4%, and dispersant property of 32.15 cm2. The biosurfactant produced is a glycolipid constituted by carbohydrate (47.7%) and lipids (50.0%). The structure was confirmed by GC‐MS (stearic acid in predominance with mass of 298 m/z), FTIR spectroscopy (polysaccharides in bands between 1025 and 1152 cm−1 and fatty acids in bands between 2057 and 3100 cm−1), 1H NMR, and 13C NMR spectrum (carbohydrates in signal of 4.38 ppm and 77.0 ppm). The properties of cleaning and degreasing of burned engine oil in cotton fabric by biosurfactant of C. echinulata was evidenced by removal of 86% of oil. After use of the biosurfactant, the fibers were not damaged, which is important for structural integrity of cotton fabric after the wash. In addition, the biosurfactant did not show toxic effect. This study suggests that the biosurfactant from C. echinulata can be used in formulation of textile detergents, in particular for removal of hydrophobic residues from the automobile industry.

Production and characterization of sophorolipids from stearic acid by solid-state fermentation, a cleaner alternative to chemical surfactants

In this manuscript, we approach the production of biosurfactants as a cleaner alternative to the chemically-produced surfactants currently used in a wide range of industries. Sophorolipids are microbially produced biosurfactants of the glycolipid type that have entered the market in select applications such as detergent or cosmetic formulation ingredients. This study focuses on sophorolipid production by the yeast Starmerella bombicola from stearic acid (C18:0), a low-cost carbon source that is difficult to work with in submerged fermentation since it remains a solid due to its high melting temperature. Consequently, optimizations of solid-state fermentation inoculated with Starmerella bombicola were studied for conversions of stearic acid and molasses to sophorolipids. Polyurethane foam functioned as the inert support. The effect of polyurethane foam density and water holding capacity was assessed and the process was optimized in terms of substrate and inoculum ratio. The best conditions were: foam with a density of 32 kg m−3 at 75% water holding capacity, 1.17:1 molasses/stearic acid (w/w) and 5% (v/w) inoculum, to obtain a yield of 0.211 g sophorolipids per g of substrates. Mass spectrometry revealed that the sophorolipids produced herein had high concentrations of diacetylated acidic and lactonic C18:0 forms. The results of interfacial properties studies revealed that C18:0 sophorolipids had promising surface tension lowering capacity and emulsification behavior. This study describes a new strategy to produce biosurfactants using low environmental impact technologies as an alternative to traditional ways to produce chemical detergents.

A novel detergent additive: Organic solvent- and thermo-alkaline-stable recombinant subtilisin

In the present work, subtilisin gene from Bacillus subtilis PTTC 1023 was synthesized, cloned into the vector pD441-NH and expressed in E. coli BL21 (DE3). Recombinant subtilisin was purified in a single-step procedure by affinity chromatography. The molecular mass of the purified protein was determined to be about 40kDa by SDS-PAGE. The optimum pH and temperature values of its proteolytic activity were 10.5 and 50°C, respectively and retained more than 70% and 89% of its activity in pH range of 7–12 and 30–60°C, respectively. Enzyme purity was estimated to be about 200- fold greater than that of the crude extract and subtilisin had a specific activity of 56.16U/mg, with a yield of about 87.9%. It was completely inhibited by phenylmethanesulfonyl fluoride, which strongly suggests its belonging to serine protease family. Interestingly, subtilisin protease displayed a significant compatibility with commercial detergents, and tolerance organic solvents, metallic ions and surfactants. The findings obtained demonstrated that protease of B. subtilis could potentially be used in future applications as an additive in detergent formulations.

Versatility and commercial status of microbial keratinases: a review

The world’s increasing population and shortage of food and feed is creating an urgently for us to look for new protein sources from waste products like keratinous waste. Poor management of these wastes has made them one of the major recalcitrant pollutants in nature. Microbial keratinases offers an economic and eco-friendly alternative for degrading and recycling keratinous waste into valuable byproducts. Diverse groups of microorganisms viz., bacteria, fungi and actinomycetes have the ability to degrade recalcitrant keratin by producing keratinase enzyme. Microbial keratinases exhibits great diversity in its biochemical properties with respect to activity and stability in various pH and temperature ranges as well as in the range of recalcitrant proteins it degrades like those present in feathers, hairs, nails, hooves etc. Owing to diverse properties and multifarious biotechnological implications, keratinases can be considered as promising biocatalysts for preparation of animal nutrients, protein supplements, leather processing, fiber modification, detergent formulation, feather meal processing for feed and fertilizer, the pharmaceutical, cosmetic and biomedical industries, and waste management. This review article presents an overview of keratin structure and composition, mechanism of microbial keratinolysis, diversity of keratinolytic microorganisms, and their potential applications in various fields.

Potential application of Bacillus subtilis SPB1 biosurfactants in laundry detergent formulations: Compatibility study with detergent ingredients and washing performance.

Surfactants play a very important role in laundry and household cleaning products ingredients. In this research, the application of lipopeptide biosurfactants, produced by Bacillus subtilis SPB1, in the formulation of a washing powder was investigated. The SPB1 biosurfactant was mixed with sodium tripolyphosphate as a builder and sodium sulfate as filler. The efficiency of the formulated detergent composition with different washing conditions to remove a stain from cotton fabric was examined. The results showed that the formulated detergent was effective in oil removal, with optimal washing conditions of pH, temperature, striate and time of washing system of 7, 65°C, 1000 RPM and 60 min, respectively. A comparative study of different detergent compositions (biosurfactant-based detergent, combined biosurfactant-commercial detergent, and a commercial detergent) for the removal of oil and tea stains, proved that the bio-scouring was more effective (>75%) in terms of the stain removal than the commercial powders (<60%). Moreover, the results demonstrated that the biosurfactant acts additively with a commercial detergent and enhances their performance from 33 to 45% in removing oil stain and from 57 to 64% in removing tea stain. As a conclusion, in addition to the low toxicity and the high biodegradability of the microbial biosurfactants, the results of this study have shown that the future use of this lipopeptide biosurfactant as laundry detergent additive is highly promising.

Cloning and characterization of a novel intracellular serine protease (IspK) from Bacillus megaterium with a potential additive for detergents

A new intracellular serine protease gene of Bacillus megaterium, ispK, encoding a protein composed of 332 amino acid residues with a predicted pI of 4.7 was cloned into Escherichia coli. The deduced amino acid sequence of IspK showed 49–56% similarity with the other microbial intracellular serine proteases described in the literature. The enzyme was effectively purified by one-step chromatography after heat-treatment, and showed a homogeneous band corresponding to 35kDa by SDS-PAGE analysis. Amino acid analysis showed that 16 amino acids of the N-terminus of IspK were removed by post-translational protease activity. The optimum pH and temperature of IspK were 6.0–7.0 and 50°C, respectively. In the presence of 2mM of Ca2+ ion, the optimum temperature was increased to 65°C and thermostability (t1/2) increased 32.9-fold from 3.3min to 108.5min at 60°C. The enzyme was activated by Ca2+ and Mg2+, almost completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and EDTA, but tolerant to nonionic surfactants, such as, Triton X-100 or Tween 80. IspK efficiently hydrolyzed natural proteins, such as, casein and hemoglobin, and improved blood stain removal. These results suggest IspK can be used as a useful additive for detergent formulations and for deproteinizations.

LCA of greywater management within a water circular economy restorative thinking framework

Greywater reuse is an attractive option for the sustainable management of water under water scarcity circumstances, within a water circular economy restorative thinking framework. Its successful deployment relies on the availability of low cost and environmentally friendly technologies. The life cycle assessment (LCA) approach provides the appropriate methodological tool for the evaluation of alternative treatments based on environmental decision criteria and, therefore, it is highly useful during the process conceptual design. This methodology should be employed in the early design phase to select those technologies with lower environmental impact. This work reports the comparative LCA of three scenarios for greywater reuse: photocatalysis, photovoltaic solar-driven photocatalysis and membrane biological reactor, in order to help the selection of the most environmentally friendly technology. The study has been focused on the removal of the surfactant sodium dodecylbenzenesulfonate, which is used in the formulation of detergents and personal care products and, thus, widely present in greywater. LCA was applied using the Environmental Sustainability Assessment methodology to obtain two main environmental indicators in order to simplify the decision making process: natural resources and environmental burdens. Energy consumption is the main contributor to both indicators owing to the high energy consumption of the light source for the photocatalytic greywater treatment. In order to reduce its environmental burdens, the most desirable scenario would be the use of solar light for the photocatalytic transformation. However, while the technological challenge of direct use of solar light is approached, the environmental suitability of the photovoltaic solar energy driven photocatalysis technology to greywater reuse has been demonstrated, as it involves the smallest environmental impact among the three studied alternatives.