Sustainable Biocatalysis: Exploiting Hemp Waste for Lipase Immobilization and Oleic Acid Esterification

Catalysts play a crucial role in various industries, including chemicals, pharmaceuticals, fuels, and energy production. Traditional synthetic chemical catalysts often require harsh conditions and complex processes [1]; on the other hand enzymatic catalysis offers a more environmentally friendly alternative, as it can occur at lower temperatures and in water-based solutions, reducing the need for hazardous chemicals [2]. Despite their advantages, free enzymes have limitations such as low stability and poor reusability. To overcome these challenges, immobilizing enzymes on solid supports has become more and more popular [3]. This approach offers several benefits, including easier product isolation, catalyst recycling, and cost-effectiveness. In today's world, where circular economy and bioeconomy principles are gaining traction, recycling and reusability are crucial for sustainable development. Insoluble biocatalysts, especially when derived from agro-industrial waste like mesoporous lignocellulosic materials, represent a viable alternative to chemical catalysis. By utilizing waste materials as enzyme supports, is possible not only to mitigate environmental burdens associated with waste disposal but also contribute to the development of resource-efficient bioprocessing technologies [4,5]. Considering the above, the primary objective of this study was to immobilize lipase from Candida rugosa onto hemp wastes through physical adsorption. The aim was to understand how the characteristics of the solid biocatalyst vary based on the type of hemp waste used as a carrier, such as hemp tea waste (HTW), hemp leaves (HL), and hemp flowers (HF). The goal was to create a solid biocatalyst that effectively retained the enzyme while maintaining high catalytic activity for producing oleic acid esters. In addition, esters like decyl oleate have become increasingly important not only in the cosmetics and personal care products industry for their excellent lubricating properties and low viscosity, but also in the production of biofuels and many other commonly used products [7,8]. They serve principally as essential emollients and conditioning agents in various cosmetics and personal care products, so are produced in enormous quantity every year. Their large production has led to the need to create new and more environmentally friendly industrial synthesis methods. One way to do this is certainly the development of solvent-free methods. The adoption of a solvent-free system in the production of oleic acid esters holds significant importance in recent decades for several compelling reasons [6]. Firstly, the elimination of solvents reduces human health and environmental impact by minimizing the release of volatile organic compounds. Moreover, solvent-free systems offer economic advantages by reducing operating costs associated with solvent procurement, handling, and disposal. In contrast, solvent-free methodologies streamline production processes, leading to cost savings and improved resource efficiency. Additionally, solvent-free systems enhance product purity and quality by eliminating the need for solvent removal steps, which can introduce impurities and compromise product integrity. This is particularly significant in industries such as cosmetics and pharmaceuticals, where product purity is crucial. Overall, the utilization of solvent-free systems in the production of oleic acid esters offers a holistic approach to sustainable manufacturing, integrating environmental, economic, and quality considerations, especially if coupled with biocatalysis carried on by enzyme immobilized on recycled and biocompatible supports like hemp wastes. By prioritizing biocompatible methodologies like the one presented, industries can achieve significant improvements in efficiency, safety, and environmental performance, paving the way for a more sustainable future.