<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Biodegradation of caffeine by the yeast <i style="mso-bidi-font-style:normal">Trichosporon asahii</i> immobilized in single and hybrid matrices</span>

Abstract

Biodegradation of caffeine by <i style="mso-bidi-font-style:normal">Trichosporon asahii</i> in freely suspended and immobilized state has been investigated under batch conditions in media containing varying concentration of sucrose and caffeine. The yeast species <i style="mso-bidi-font-style:normal">T. asahii</i> is immobilized in single and hybrid matrices such as Na-alginate, polyvinyl alcohol (PVA)-alginate and glycerol-alginate.&nbsp; Degradation of caffeine and growth of <i style="mso-bidi-font-style:normal">T. asahii</i> are found to be optimum when 8 g/L sucrose and 10 g/L caffeine are present in the medium. PVA-alginate immobilized cells show the maximum caffeine degradation compared to free and other immobilized cells. Bead diameter shows profound effect on biodegradation rate, diffusivity, effectiveness factor and Thiele modulus. In column mode, 98.9% caffeine degradation in effluent is obtained at optimized flow rate of 1 mL/min and bed height of 12 cm using PVA-alginate immobilized <i style="mso-bidi-font-style:normal">T. asahii</i> cells. Successful attempt on caffeine removal from wastewater has also been made using the same hybrid beads.