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

Figure 4

(a) Effect of organic solvents on the stability of the purified rSAPV, SPVP, and Thermolysin type X. Various organic solvents, with different log P values (50%, v/v), were tested at 190 strokes per min and 37°C for 3 days to evaluate their effects on peptidase stability. The residual peptidase activities were assayed under the same conditions of each enzyme. The activity of the enzyme without any organic solvent was taken as 100%. The activity is expressed as a percentage of activity level in the absence of organic solvents. Each point represents the mean of three independent experiments. Performance evaluation of the purified SAPV peptidase. (b) Stability of rSAPV, Alcalase 2.4 L FG, and Bioprotease N100L in the presence of liquid and solid laundry detergents. The list of liquid detergents included: Class (EJM, Sfax, Tunisia), EcoVax and Dipex (Klin Productions, Sfax, Tunisia), Skip (Unilever, France), and Nadhif (Henkel-Alki, Tunisia). The solid detergents used were OMO (Unilever, France), Det (Sodet, Sfax, Tunisia), Dixan (Henkel-Alki, Tunisia), iSiS (Henkel, Algiers, Algeria), and Ariel (Procter & Gamble, Switzerland). Peptidase activity of the control sample, which contained no additive and incubated under similar conditions, was taken as 100%. Vertical bars indicate standard error of the mean (n = 3). Washing performance analysis of rSAPV and commercial enzymes (500 U/mL) using egg (c), blood (d), and chocolate (e) stains with Class detergent (7 g/L). Stained cloths were washed with tap water (A), Class detergent (B), Class added with Alcalase 2.4 L FG (C), Class added with Bioprotease N100L (D), and Class added with rSAPV (E). I: untreated clothes (control) and II: treated clothes.

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