Optimum conditions for surface modification of PET by lipase enzymes produced by Egyptian bacilli in comparison with standard one

Abstract

<span style="mso-fareast-font-family: AdvOT863180fb;mso-bidi-language:AR-EG" lang="EN-GB">The optimum conditions for surface modification of polyethylene terephthalate (PET) by lipase enzymes produced under economic conditions by two Egyptian bacilli (<i><span style="mso-bidi-language:AR-EG" lang="EN-GB">Bacillus </span></i><span style="mso-bidi-language:AR-EG" lang="EN-GB">isolate 6C and <i>Bacillus </i>isolate 5W) have been obtained and then compared with reference sample. The optimum conditions are found to be 0.04 mg/mL enzyme concentration, 0.5 h incubation time, room temperature (25 ºC) and <i>p</i>H 8 under shaking conditions. Addition of 0.15% CaCl₂<span style="mso-fareast-font-family:AdvOT863180fb; mso-bidi-language:AR-EG" lang="EN-GB"> to the treatment bath enhances both the hydrophilicity (18-26%) and dyeability (22- 194%). <span style="mso-bidi-language:AR-EG" lang="EN-GB">The effect of hydrolytic activity of enzymatic process on the weight loss after treatment does not show any significant difference. Printing both untreated and treated PET fabrics with transfer printing shows high leveling properties w.r.t. ∆E values, where it is considered as acceptable values of color differences. PET treated with different sources of lipase enzyme under optimum conditions shows good physical properties and high water regain. SEM of the surface of lipase treated PET samples shows cracks and voids compared to smooth surface of untreated PET fabrics.

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