Harmful Effect of Detergents on Lipase

In Silico and Experimental Studies on the Effect of α3 and α5 Deletion on the Biochemical Properties of Bacillus thermocatenulatus Lipase

To investigate the effect of α3 and α5 helices on the biochemical characterization of Bacillus thermocatenulatus lipase (BTL2), both helices were deleted from native BTL2 lipase. After structural modeling and characterization, the truncated btl2 gene (Δbtl2) was cloned into E. coli BL21 under the control of the T7 promoter. After cultivation and induction of the recombinant bacteria, the Δα3α5 lipase was purified by Ni-NTA column chromatography. Next, the biochemical properties of the Δα3α5 lipase were compared with the previously expressed and purified native lipase. In the presence of the substrate tributyrin (C4), the maximum activity of native and Δα3α5 lipase was 9360 and 5000 U/mg, respectively. The deletion changed the substrate specificity from tributyrin (C4) to tricaprylin (C8) substrate. Native and Δα3α5 lipase showed similar activity patterns at all temperatures and pH values, with the activity of Δα3α5 lipase being approximately 20% lower than native lipase. Triton X100 increased the activity of native and Δα3α5 lipases by 2.1- and 2.5-fold, respectively.

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.

Detection of domestic detergent residues on porcelain tableware using laser induced breakdown spectroscopy

Domestic detergents are widely used and the detection of detergent residues on tableware is closely related to people's health. Using LIBS to detect detergent rapidly has a promising potential.

Study of Different Hueing Dyes Deposition on Fabrics during Home Laundry

The objective of this research was to study the deposition mechanism of hueing dyes on different fabric surfaces. In this study, two types of fabrics and four types of hueing dyes were used to study the dye accumulation behaviors on fabric samples. The results showed that nylon and cotton treated with hueing dyes had a lower b* value and a higher CIE whiteness. Furthermore, the accumulation level of hueing dyes on nylon was much higher than on cotton fabric. The chemical composition of fabrics and molecular structures of hueing dyes were also investigated to study the interactions between different fibers and dyes. The results showed that the over-deposition of hueing dyes on fabric was mainly driven by the electrostatic forces, which could be weakened by adding salts to neutralize the fabric surface charge during home laundry.

Effect of ethyleneoxide groups of anionic surfactants on lipase activity

The use of enzymes in laundry and dish detergent products is growing. Such tendency implies dedicated studies to understand surfactant-enzyme interactions. The interactions between surfactants and enzymes and their impact on the catalytic efficiency represent a central problem and were here evaluated using circular dichroism, dynamic light scattering, and enzyme activity determinations. This work focuses on this key issue by evaluating the role of the ethyleneoxide (EO) groups of anionic surfactants on the structure and activity of a commercial lipase, and by focusing on the protein/surfactant interactions at a molecular level. The conformational changes and enzymatic activity of the protein were evaluated in the presence of sodium dodecyl sulfate (SDS also denoted as SLE₀ S) and of sodium lauryl ether sulfate with two EO units (SLE₂ S). The results strongly suggest that the presence of EO units in the surfactant polar headgroup determines the stability and the activity of the enzyme. While SDS promotes enzyme denaturation and consequent loss of activity, SLE₂ S preserves the enzyme structure and activity. The data further highlights that the electrostatic interactions among the protein groups are changed by the presence of the adsorbed anionic surfactants being such absorption mainly driven by hydrophobic interactions. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1276-1282, 2016.

The application of laser-induced breakdown spectroscopy in domestic detergent residues detection

With the increasingly wide application of detergents, the hazards of detergent residues have gained extensive attention.