Valorization of Aloe barbadensis Miller. (Aloe vera) Processing Waste

Aloe vera plant is known worldwide for its medicinal properties and application in gel-based products such as shampoo, soap, and sunscreen. However, the demand for these gel-based products has led to a surplus production of Aloe vera processing waste. An Aloe vera gel processing facility could generate up to 4000 kg of Aloe vera waste per month. Currently the Aloe vera waste is being disposed to the landfill or used as fertilizer. A sustainable management system for the Aloe vera processing waste should be considered, due to the negative societal and environmental impacts of the currents waste disposal methods. Therefore, this review focuses on various approaches that can be used to valorize Aloe vera waste into value-added products, such as animal and aquaculture feeds, biosorbents, biofuel and natural polymers. Researchers have reported Aloe vera waste for environmental applications biosorbents used for wastewater treatment of various pollutants. Several studies have also reported on the valorization of Aloe vera waste for production of biofuels such as bioethanol, mixed alcohol fuels, biogas and syngas. Aloe vera waste could also be valorized through isolation and synthesis of natural polymers for application in wound dressing, tissue engineering and drug delivery systems. Aloe vera waste valorization was also reviewed through extraction of value-added bioactive compounds such as aloe-emodin, aloin and aloeresin. These value-added bioactive compounds have various applications in the cosmetics (non-steroidal anti-inflammatory, tyrosinase inhibitors) and pharmaceutical (anticancer agent and COVID 19 inhibitors) industry.