Impact of Support Material on Candida rugosa Lipase Immobilization Performance

The use of lignocellulosic waste materials is becoming increasingly popular in the scientific landscape due to an ever-increasing drive towards a circular economy [1]. In fact, lignocellulosic wastes represent a large portion of the waste produced by the forestry and agriculture industries and can lead to a large environmental impact if not disposed correctly. Using these wastes as supports for enzymatic immobilization allows not only to recycle them but also to transform them into products with great added value [2]. Indeed, immobilized enzymes have considerable potential for their use in industrial processes thanks to their greater stability in harsh environments and the possibility of reusing the solid biocatalyst in more production cycles and keeping it active for a longer time during storage [3]. However, the integration of enzymes into industrial processes via immobilization is a complex effort, influenced by numerous factors including enzyme characteristics and environmental variables. Central to this process is the selection of the optimal immobilization method and suitable support materials, necessitating properties such as high surface area, mechanical strength, and compatibility with the enzyme. For this reason, this study investigates the immobilization of lipase from Candida Rugosa (CRL) on lignocellulosic wastes derived from rice husk (RH), brewer’s spent grain (BSG), hemp tea waste (HTW), green tea waste (GTW), vine bark (VB), and spent coffee grounds (SCG), focusing on the characterization of these materials and their impact on the lipase-support interaction. The wastes underwent thorough characterization through ATR-FTIR, BET, and SEM analysis, as well as assessments of lignin content and surface hydrophobicity. Analysis of factors impacting immobilization efficacy underscored the significance of hydrophobic interactions. Examination of enzymatic desorption, triggered by varying ionic strength and detergent treatments, highlighted a blend of hydrophobic and electrostatic interactions across most supports, with HTW and GTW showcasing a dominance of hydrophobic interactions. Notably, HTW and SCG emerged as better carriers, displaying superior immobilization performance with the highest activity recovery (%), immobilization yield (%), immobilization efficiency (%), and immobilized activity (U/g).