Detergent Formulations Research Articles

Rapid and Simple Identification and Quantification of Components in Detergent Formulations by Nuclear Magnetic Resonance Spectroscopy

AbstractA rapid, inexpensive, and simple high‐resolution NMR spectroscopic method is outlined for determining the content of surfactants and other low‐molecular‐weight organic compounds in detergent formulations. With simple sample preparation, quantitative results can be obtained from an internal standard and/or the method can be used as a fingerprint analysis of the surfactant composition. The NMR sample is prepared by suspending the detergent sample in deuterated acetic acid and thus dissolving surfactants and other organic compounds. Any content of carbonate will be liberated as CO2, whereas other inorganic materials are removed by centrifugation. From one‐dimensional 1H and two‐dimensional HSQC NMR spectra, the surfactant components and low‐molecular‐weight organic compounds can be identified from reference spectra. Intensities of signature signals in the one‐dimensional 1H NMR spectrum are used for quantification by comparing with an internal standard. Furthermore, it is demonstrated how 31P NMR can be used to identify and quantify phosphonate‐type chelators.

Identification of a New Serine Alkaline Peptidase from the Moderately Halophilic Virgibacillus natechei sp. nov., Strain FarDT and its Application as Bioadditive for Peptide Synthesis and Laundry Detergent Formulations.

A new peptidase designated as SAPV produced from a moderately halophilic Virgibacillus natechei sp. nov., strain FarDT was investigated by purification to homogeneity followed by biochemical and molecular characterization purposes. Through optimization, it was determined that the optimum peptidase activity was 16,000 U/mL. It was achieved after 36 h incubation at 35°C in the optimized enzyme liquid medium (ELM) at pH 7.4 that contains only white shrimp shell by-product (60 g/L) as sole energy and carbon sources. The SAPV enzyme is a monomer protein with a molecular mass of 31 kDa as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance liquid chromatography (HPLC) gel filtration chromatography. The sequence of its NH2-terminal amino-acid residues showed homology with those of Bacillus peptidases S8/S53 superfamily. The SAPV showed optimal activity at pH 9 and 60°C. Irreversible inhibition of enzyme activity by diiodopropyl fluorophosphates (DFP) and phenylmethanesulfonyl fluoride (PMSF) confirmed its belonging to the serine peptidases. Considering its interesting biochemical characterization, the sapV gene was cloned, sequenced, and heterologously overexpressed in the extracellular fraction of E. coli BL21(DE3)pLysS. The biochemical properties of the recombinant peptidase (rSAPV) were similar to those of the native one. The highest sequence identity value (97.66%) of SAPV was obtained with peptidase S8 from Virgibacillus massiliensis DSM 28587, with 9 amino-acid residues of difference. Interestingly, rSAPV showed an outstanding and high resistance to several organic solvents than SPVP from Aeribacillus pallidus VP3 and Thermolysin type X. Furthermore, rSAPV exhibited an excellent detergent stability and compatibility than Alcalase 2.4 L FG and Bioprotease N100L. Considering all these remarkable properties, rSAPV has attracted the interest of industrialists.

Biosurfactants from Waste: Structures and Interfacial Properties of Sophorolipids Produced from a Residual Oil Cake

AbstractSophorolipids (SL) are microbial biosurfactants that have entered the market as detergent and cosmetic formulation ingredients. Current research is focused on the use of wastes to decrease the final production costs of SL and the environmental impacts. SL from wastes will help to move toward the circular economy only if the SL produced this way are pure enough and as efficient as current commercial SL. This manuscript focuses on the study of the structures and the interfacial properties of a crude SL natural mixture produced by solid‐state fermentation from a residual sunflower oil cake from the oil‐refining industry. Liquid chromatography–mass spectrometry (LC–MS) demonstrated that the diacetylated lactonic 18:1 SL was the most abundant SL of the mixture, followed by the correspondent acidic form. The surface tension‐lowering capacity was studied in a water–air interface at temperatures ranging from 15 to 50 °C. The minimum surface tension and critical micelle concentration were determined. The emulsion properties were similar to those obtained for the commercial nonionic surfactant Triton X‐100. The efficiency of the SL natural mixture was also proven successful for the displacement of a diesel slick. These results confirmed the effectiveness of SL produced from a real waste.

Lipase of Pseudomonas guariconesis as an additive in laundry detergents and transesterification biocatalysts.

A newly isolated culture, Pseudomonas guariconesis, is reported for the first time for lipase production. Various process parameters affecting enzyme production were optimized through statistical design experiments. The Plackett-Burman experimental design was used for screening 10 parameters for lipase production, which was further optimized using the central composite design of response surface methodology. Maximum lipase activity of 220 U/ml was obtained after 24 h of incubation in shake-flask cultures with an inoculum concentration of 0.6% v/v, incubation temperature of 30°C, and medium pH 9.0. Castor oil (0.5% v/v) was used as the inducer for lipase production. The enzyme was found to be compatible with five different commercial detergents, indicating its potential to be used in detergent formulations. It also acted as a biocatalyst in a transesterification process. The alkaline enzyme was found to be stable in the presence of bleaching agents, metal ions, and organic solvents as well.

Low‐Toxic and Nonirritant Biosurfactant Surfactin and its Performances in Detergent Formulations

AbstractDeveloping eco‐friendly, nonirritant, low‐toxic, and high‐efficient surface active ingredients for detergents is an ongoing challenge in the detergent field. Surfactin is one of the representative lipopeptides produced by microorganisms. In this article, we report the surfactin isolated from cell‐free broth of Bacillus subtilis HSO121 and purified by reversed‐phase high‐performance liquid chromatography for detergent formulations. The biodegradability, acute dermal irritation, acute oral toxicity (LD50 and LC50), surface activity, washing efficiency, and compatibility with hard water of the purified biosurfactant surfactin have been studied to explore the feasibility for applications of the surfactin in detergents. Acute oral toxicity tests (LD50 > 5000 mg kg−1, LC50 > 1000 mg kg−1) and skin irritation tests (PII = 0) indicate that the surfactin is a low‐toxic and nonirritant ingredient for detergent formulation. Moreover, the surfactin shows excellent surface and interfacial properties of emulsification and wettability, high compatibility, and stability in a wide range of temperatures, pH, and hard water and acceptable properties in biodegradability and foaming ability, which suggests that the biosurfactant surfactin is a promising ingredient for detergent formations in our daily life and for industrial applications.

Aggregation properties of cold-active lipase produced by a psychrotolerant strain of Pseudomonas palleroniana (GBPI_508)

The present study aims to exploit microbial potential from colder region to produce lipase enzyme stable at low temperatures. A newly isolated bacterium GBPI_508 from Himalayan environment, was investigated for the production of cold-active lipase emphasizing on its aggregation properties. Plate based assays followed by quantitative production of enzyme was estimated under different culture conditions. Further characterization of partially purified enzyme was done for molecular weight determination and activity and stability under varying conditions of pH, temperature, and in presence of organic solvents, inhibitors, and metal ions. The psychrotolerant bacterium was identified as Pseudomonas palleroniana following 16S rRNA gene sequencing. Maximum lipase production by GBPI_508 was recorded in 7 days at 25 °C utilizing yeast extract as nitrogen source and olive oil as substrate in the lipase production medium. Triton X-100 (1%) in the medium as emulsifier significantly enhanced the lipase production. Lipase produced by bacterium showed aggregation which was confirmed by dynamic light scattering and native PAGE. SDS-PAGE followed by zymogram analysis of partially purified enzyme showed two active bands of ∼50 kDa and ∼54 kDa. Optimum activity of partially purified enzymatic preparation was recorded at 40 °C while the activity remained nearly consistent from pH 7.0 to 12.0, whereas, maximum stability was recorded at pH values 7.0 and 11.0 at 25 °C. Interestingly, lipase in the partially purified fraction retained 60% enzyme activity at 10 °C. Medium chain pNP ester (C10) was the most preferred substrate for the lipase of GBPI_508. The lipase possessed >50% residual activity when incubated with different organic solvents (25% v/v) except toluene and dichloromethane which inhibited the activity below 50%. Partially purified enzyme was also stable in the presence of metal ions and inhibitors. The study suggests applicability of GBPI_508 lipase in low temperature conditions such as cold-active detergent formulations and cold bioremediation.

Environmental and energetic effects of cleaner production scenarios on the Sodium Lauryl Ether Sulfate production chain

Abstract Sodium Lauryl Ether Sulfate is an important surfactant used by the Specialty Chemical Industry. However, little quantitative information regarding its environmental impacts in a systemic perspective is available. Therefore, this study assessed the environmental performance of 1.0 ton of Sodium Lauryl Ether Sulfate containing 3 mol of ethylene oxide (SLES 3EO), by means of a ‘cradle-to-gate’ Life Cycle Assessment. Environmental impacts were quantified in terms of Global Warming Potential and Primary Energy Demand (PED). Carbon Footprint was also estimated according to ISO 14067 guidelines. The Global Warming indicator was calculated as 1.87 t CO2eq/t for the baseline scenario, while PED was estimated as 71.7 GJ/t. Based on the main sources of impact, four individual alternatives aiming at environmental performance improvement were proposed, based on the Resource Efficient and Cleaner Production philosophy: S1) production using palm kernel oil from Brazil; S2) production from synthetic lauryl alcohol; S3) generation of thermal energy from biomass; S4) SLES 3EO synthesis using ethylene oxide obtained from sugarcane. Possible synergies deriving from the combinations of these propositions were also assessed, considering seven additional scenarios (S5 – S11). It was observed that lauryl alcohol performance was very influential and decisive for the results. Moreover, thermal energy from biomass was beneficial in terms of Global Warming, while increasing the renewable fraction of the PED indicator. On the other hand, ethylene oxide production from sugarcane ethanol was not an advantageous alternative, due to high fuel and thermal energy demands throughout its production chain. The Carbon Footprint assessment according to the ISO 14067 standard indicates a beneficial change in the impact profiles between the scenarios presenting renewable source assets participating in their life cycle, with a strong reduction in relation to the results obtained by applying the IPCC approach. Synergy among cleaner production propositions was observed and highly influenced by the amount of biomass incorporated to SLES 3EO life cycle. This can be considered an innovative approach regarding the Brazilian context. As a pioneer initiative, it is expected that the outcomes from this investigation would contribute to future initiatives investigating detergent formulation from an environmental perspective.

Combined Use of Streaming Potential and UV/Vis To Assess Surface Modification of Fabrics via Soil Release Polymers

Polymers have become a widespread part of laundry detergent formulations because of their benefits which are usually delivered via surface modification of fibers. Therefore, there is a growing interest in understanding their deposition on fabrics. In this work, we have used streaming potential to assess changes in surface charge of polyester and knitted cotton after modification via soil release polymers (SRPs). Results identify a relationship between the measured zeta potential for the modified fabrics and the charge of the polymer. The effects of parameters, such as agitation speed and bulk concentration during deposition, have been investigated. Streaming potential data were then correlated to adsorption isotherms from UV absorbance data, and a Langmuir–Freundlich model was proposed to describe the isotherms for polyester. The stain removal index for some common hydrophobic stains was determined via image analysis. A link between SRP deposition efficiency and their effectiveness on greasy soil removal was observed.

Purification and biochemical characterization of a novel thermostable protease from the oyster mushroom Pleurotus sajor-caju strain CTM10057 with industrial interest

BackgroundProteases are hydrolytic enzymes that catalyze peptide linkage cleavage reactions at the level of proteins and peptides with different degrees of specificity. This group draws the attention of industry. More than one protease in three is a serine protease. Classically, they are active at neutral to alkaline pH. The serine proteases are researched for industrial uses, especially detergents. They are the most commercially available enzyme group in the world market. Overall, fungi produced extracellular proteases, easily separated from mycelium by filtration.ResultsA new basidiomycete fungus CTM10057, a hyperproducer of a novel protease (10,500 U/mL), was identified as Pleurotus sajor-caju (oyster mushroom). The enzyme, called SPPS, was purified to homogeneity by heat-treatment (80 °C for 20 min) followed by ammonium sulfate precipitation (35–55%)-dialysis, then UNO Q-6 FPLC ion-exchange chromatography and finally HPLC-ZORBAX PSM 300 HPSEC gel filtration chromatography, and submitted to biochemical characterization assays. The molecular mass was estimated to be 65 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Native-PAGE, casein-zymography, and size exclusion by HPLC. A high homology with mushroom proteases was displayed by the first 26 amino-acid residues of the NH2-terminal aminoacid sequence. Phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP) strongly inhibit SPPS, revealing that it is a member of the serine-proteases family. The pH and temperature optima were 9.5 and 70 °C, respectively. Interestingly, SPPS possesses the most elevated hydrolysis level and catalytic efficiency in comparison with SPTC, Flavourzyme® 500 L, and Thermolysin type X proteases. More remarkably, a high tolerance towards organic solvent tolerance was exhibited by SPPS, together with considerable detergent stability compared to the commercial proteases Thermolysin type X and Flavourzyme® 500 L, respectively.ConclusionsThis proves the excellent proprieties characterizing SPPS, making it a potential candidate for industrial applications especially detergent formulations.

Stability studies of an amylase and a protease for cleaning processes in the food industry

An α-amylase and a protease suitable to be used as detergent additives in Cleaning-In-Place processes in the food industry have been studied in terms of their stability during storage as well as under washing conditions. Enzymatic solutions have been prepared with addition of two non-ionic surfactants at the pH of operation, an amine oxide and an alkylpolyglucoside. Activity assays have been carried out in order to obtain deactivation kinetics. The study of stability at storage during 21 days at 40°C and 60°C reveals that the enzymatic solutions in the absence of surfactants preserve their activity for longer. The protease showed to be more sensitive to thermal deactivation, undergoing a complete loss of activity at 60°C before 24h in all solutions studied. On the other hand, activity assays have been carried out at concentrations, time and temperature values usually found during cleaning processes of hard surfaces. The presence of the alkylpolyglucoside showed to preserve enzymatic activity of α-amylase at all temperatures assayed. The amine oxide, nevertheless, seemed to contribute to α-amylase deactivation and did not have a significant effect on protease. The results of this work suggest the need of stabilize enzymes in detergent formulations even when they do not contain potential denaturants.

A strategic approach of enzyme engineering by attribute ranking and enzyme immobilization on zinc oxide nanoparticles to attain thermostability in mesophilic Bacillus subtilis lipase for detergent formulation

The present study envisaged rationalized protein engineering approach to attain thermostability in a mesophilic Bacillus subtilis lipase. Contributing amino acids for thermostability were analyzed from homologous thermophilic-mesophilic protein dataset through relative abundance and generated ranking model. Analyses divulged priority of charged amino acids for thermostability. Ranking model was used to predict thermostabilizing mutations. Three lipase mutants, bsl_the1 (V149K, Q150E), bsl_the2 (F41K, W42E, V149K, Q150E) and bsl_the3 (F41K, W42E, P119E, Q121K, V149K, Q150E) were generated and validated through in silico and in vitro approaches for improved activity and thermostability. ZnO nanoparticles were synthesized by precipitation method and functionalized using polyethylenimine, APTES and glutaraldehyde for lipase immobilization. The immobilization was confirmed through various analytical techniques. Analysis revealed bsl_wt showed optimum activity at 35 °C and pH 8 which was increased to 60 °C and pH 10 in case of ZnO-bsl_the3. The ZnO-bsl_the3 showed 80% of their initial activity after 60 days of storage stability and retained 78% of activity after 20 cycles of reuse. Lipases were applied for oil and grease stain removal from fabric. ZnO-bsl_the3 removed 90% and 82% of oil and grease stains, respectively. Conclusively, it revealed a promising perspective of low-cost nanobiocatalysts in detergent formulation.

Profiling Protease Activity in Laundry Detergents with Peptide Arrays and SAMDI Mass Spectrometry

Laundry detergent formulations include proteases to digest and clean protein-based stains. Methods that can profile protease activity and specificity in detergents could be important in guiding the...

Purification and biochemical characterization of an organic solvent-tolerant and detergent-stable lipase from Staphylococcus capitis.

A mesophilic bacterial culture, producing an extracellular alkaline lipase, was isolated from the gas-washing wastewaters generated from the Sfax phosphate plant of the Tunisian Chemical Group and identified as Staphylococcus capitis strain. The lipase, named S. capitis lipase (SCL), has been purified to homogeneity from the culture medium. The purified enzyme molecular weight was around 45 kDa. Specific activities about 3,900 and 500 U/mg were measured using tributyrin and olive oil emulsion as substrates, respectively at 37°C and pH 8.5. Interestingly, the SCL maintained more than 60% of its initial activity over a wide pH values ranging from 5 to 11 with a high stability between pH 9 and 11 after 1 hr of incubation at room temperature. The lipase activity was enhanced in the presence of 2 mM of Mg2+ , Ca2+ , and K+ . SCL showed significant stability in the presence of detergents and organic solvents. Altogether, these features make the SCL useful for industrial applications. Besides, SCL was compatible with commercially available detergents, and its incorporation increases lipid degradation performances making it a potential candidate in detergent formulation.

Synthesis and Foaming Performance of Lauramidopropyl Betaine Derivate Surfactants

The ampholytic surfactant Lauramidopropyl betaine (LAB) is a multifunctional amphoteric surfactant, which is widely used in washing formulations and is the main component of many softeners and detergent formulations. It has the advantages of less irritation to skin, mild performance and easy biodegradability. It is superior to other amphoteric surfactants. In this paper, new surfactants were synthesized by using LAB as the main component and the molar ratios of LAB to formaldehyde were 1:1, 1:2, 1:3 and 1:4, respectively. The new functional group hydroxymethyl was introduced into the LAB, and the effect of hydroxymethyl on the properties of raw materials was discussed. And the surface properties were studied, including high temperature resistance, methanol resistance and salt resistance. The results showed that the high temperature resistance of R2 is better below 50 °C, R0 has better high temperature resistance above 50 °C; In the aspect of methanol resistance, the methanol resistance of R4 is better at 10% and 20% methanol content; The effect of R0 is better in salt resistance. Finally, it can be concluded that the introduction of methylol groups improves the performance of the prepared new surfactants in certain properties.

The application of a halotolerant metalloprotease from marine bacterium Vibrio sp. LA-05 in liquid detergent formulations

The application of a halotolerant metalloprotease from marine bacterium Vibrio sp. LA-05 in liquid detergent formulations was investigated in detail. The washing simulation experiment revealed that blood stains were successfully removed from cotton cloths by washing them with three commercial liquid detergents (Liby, Bluemoon and Walch) supplemented with the crude protease at 15–45 °C for 30 min. However, macroscopic residues of stains were remained on the cloths treated with tap water, liquid detergent alone and liquid detergent supplemented with the commercial protease subtilisin A. The analyses of microstructure, chemical elements and tensile properties showed that the washing treatments with crude protease as a bio-additive almost did not affect the texture, elemental composition or tensile properties of cloths. Sheep blood agar plate and SDS-PAGE analyses indicated that its hydrolysis activity to blood proteins was not significantly influenced even in the presence of liquid detergents. The hydrolysis mechanism was further studied and results demonstrated that this protease could specifically hydrolyzed six proteins in Sheep Red Blood Cells (SRBCs) and four proteins in sheep plasma. These findings suggest that this crude halotolerant metalloprotease as a bio-additive may have considerable potentials in the application of liquid detergent formulations.

Biochemical Characterization of Heat-Tolerant Recombinant L-Arabinose Isomerase from Enterococcus faecium DBFIQ E36 Strain with Feasible Applications in D-Tagatose Production.

D-Tagatose is a ketohexose, which presents unique properties as a low-calorie functional sweetener possessing a sweet flavor profile similar to D-sucrose and having no aftertaste. Considered a generally recognized as safe (GRAS) substance by FAO/WHO, D-tagatose can be used as an intermediate for the synthesis of other optically active compounds as well as an additive in detergent, cosmetic, and pharmaceutical formulations. This study reports important features for L-arabinose isomerase (EC 5.3.1.4) (L-AI) use in industry. We describe arabinose (araA) gene virulence analysis, gene isolation, sequencing, cloning, and heterologous overexpression of L-AI from the food-grade GRAS bacterium Enterococcus faecium DBFIQ E36 in Escherichia coli and assess biochemical properties of this recombinant enzyme. Recombinant L-AI (rL-AI) was one-step purified to homogeneity by Ni2+-agarose resin affinity chromatography and biochemical characterization revealed low identity with both thermophilic and mesophilic L-AIs but high degree of conservation in residues involved in substrate recognition. Optimal conditions for rL-AI activity were 50°C, pH 5.5, and 0.3mM Mn2+, exhibiting a low cofactor concentration requirement and an acidic optimum pH. Half-life at 45°C and 50°C were 1427h and 11h, respectively, and 21.5h and 39.5h at pH 4.5 and 5.6, respectively, showing the high stability of the enzyme in the presence of a metallic cofactor. Bioconversion yield for D-tagatose biosynthesis was 45% at 50°C after 48h. These properties highlight the technological potential of E. faecium rL-AI as biocatalyst for D-tagatose production.

Prediction of self-heating in detergent powders for application to spray dryer wall accumulations

During the spray drying of detergent formulations, powder can accumulate on the inner walls of the spray drying tower. Under certain conditions, when the accumulations are large enough, self-heating can occur. This leads to unwanted charring and in severe cases to thermal runaway. In this study, basket heating methods, namely the steady-state approach and cross-point temperature method, were used to estimate the zero-order kinetics of the self-heating reaction of a typical detergent formulation. It was found that the resulting kinetics of these two methods were not in agreement, with this being attributed to the cross-point temperature method’s sensitivity to errors. The estimated kinetics were used in a 2D-axisymmetric transient model of heat transfer within an oven heated basket of detergent powder. Temperature-time profiles, and critical ambient temperatures, predicted by the model agreed well with experimental measurements. The model was also used to explore the value of using nth-order kinetics that were estimated using a thermogravimetric measurement technique. Theses kinetic showed no benefit over the zero-order kinetics and introduced unnecessary complexity. Future work will see this model and the insights gained applied to the problem of modeling self-heating in spray dryer wall accumulations.

Valorization of fruit by-products of Bromelia antiacantha Bertol.: Protease obtaining and its potential as additive for laundry detergents

Abstract The aim of this work is to isolate and study the performance of an alkaline protease from fruit by-products of Bromelia antiachanta Bertol. for its potential application as an additive of laundry detergent formulations. Its behavior is compared with Pura Felt 4000 (Genencor Argentina). Antiacanthain, a cysteine protease from fruit by-products of B. antiachanta, showed a remarkable stability (50 ± 0.82% to 177 ± 0.82% residual activity) in buffer with non-ionic and cationic surfactants (0.1, 0.4 and 1.0%), metal chelation (1, 5 and 10 mM EDTA), antiredepositant (100 mM Na2CO3) and bleaching (5% H2O2) agents. In commercial detergents, antiacanthain retained 100 ± 1.25% to 120 ± 0.82% of its maximum activity at 60 °C and removed stains from cloths in a short time period. Antiacanthain fulfilled all the requirements as detergent additive: high activity and stability in a broad temperature range (25–60 °C) and alkaline pH (5–9), and very good compatibility with commercial detergents.

Sunflower Acid Oil‐Based Production of Rhamnolipid Using Pseudomonas aeruginosa and Its Application in Liquid Detergents

AbstractUtilization of industrial waste as substrates for the rhamnolipid synthesis by Pseudomonas aeruginosa is a worthy alternative for conventionally used vegetable oils and fatty acids to reduce the production cost of rhamnolipid. Sunflower acid oil (SAO), a by‐product of the oil industry, contains 70% 18:0 fatty acid, with oleic acid as a major component. In this scope, production and analysis of rhamnolipid was successfully demonstrated using SAO as a new substrate. Pseudomonas aeruginosa produced rhamnolipid (a glycolipid biosurfactant) at a maximum concentration of 4.9 g L−1 with 60 g L−1 of SAO in the medium. Structural properties of rhamnolipid biosurfactant are confirmed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and fourier transformed infrared spectroscopy (FTIR) analysis. Further surface‐active properties of the crude rhamnolipid were evaluated by measuring surface tension and emulsification properties. The synthesized rhamnolipid reduced the surface tension of water to 30.12 mN m−1 and interfacial tension (against heptane) to 0.52 mN m−1. Moreover, rhamnolipid shows the highest emulsification index (above 80%) for vegetable oils. This study confirms the use of SAO as a potential substrate for rhamnolipid production. The synthesized rhamnolipid was incorporated in liquid detergent formulation along with alpha olefin sulfonate (AOS) and sodium lauryl ether sulfate (SLES). The performance properties including foaming and cleaning efficiency of liquid detergent were compared.

Characterization of an extreme alkaline-stable keratinase from the draft genome of feather-degrading Bacillus sp. JM7 from deep-sea

Bacillus sp. JM7, a strain isolated from the deep-sea of the South China Sea, was found to efficiently degrade 79.4% native chicken feather within 30 h. Scanning electron microscopy analysis showed that JM7 strain could gradually degrade feather by modifying the microstructure of feather keratin. A total of 25 protease genes were predicted from the draft genome of JM7 strain, among which a predicted subtilisin-like serine protease (designated as Ker02562) was further characterized for its keratinolytic activity. The recombinant Ker02562 functioned at a wide range of temperatures from 30°C to 60°C, with an optimum at 40–50°C. Ker02562 was highly active at various pHs ranging from 5.0 to 13.0, with a maximum activity observed at pH 7.0–9.0. Remarkably, recombinant Ker02562 was stable in extreme alkaline environments (pH 10–13), which was much better than most other reported keratinases. Collectively, these favorable properties could make Bacillus sp. JM7 and Ker02562 attractive to be applied in the detergent formulation and feather bioconversion.