Immobilization of Kluyveromyces lactis for xylose production using different lignocellulosic materials as carbon sources

Abstract

Lignocellulosic biowaste is a renewable and abundant resource with significant potential for the production of value-added products such as xylose which is a major intermediary in the biofuel, bioplastic, and pharmaceutical sectors. However, problems such as inefficient bioconversion and instability of free-cell fermentation systems limit its industrial application. This research investigates the use of immobilized recombinant Kluyveromyces lactis for xylose production using various lignocellulosic biowastes such as sugarcane bagasse, corn stover, rice straw, oil palm fronds, and banana leaves. The biowastes were washed, dried, ground, and pre-treated with 1% sodium hydroxide (NaOH) solution. K. lactis cells were cultivated in yeast peptone dextrose (YPD) medium and immobilized in 2% sodium alginate beads cross-linked with 0.1 M calcium chloride (CaCl2). Fermentation was carried out at 30 °C and 150 rpm for 24 hours using 1 g of pre-treated biomass and immobilized yeast beads in 100 mL of YPD medium. Reducing sugar concentration was determined using the dinitro salicylic acid (DNS) method, while yeast growth and pH changes were monitored. Results demonstrated that immobilized K. lactis could produce xylose production across all biowaste types, with sugarcane bagasse and corn stover yielding the highest reducing sugar concentrations. However, a further optimization is needed to increase the enzyme production from the immobilized cell systems. The findings highlight a cost-effective and environmentally friendly approach for improving industrial xylose production through K. lactis immobilization on lignocellulosic biowastes.