The world’s demand for energy is currently increasing rapidly due to continuous vehicle production and massive industrial development. This has led to excessive exploitation of fossil fuel resources. Moreover, the combustion of fossil fuels also exacerbates the negative environmental impact associated with global warming. On the other hand, industrial processes in the agricultural sector always generate waste that, if disposed of directly, can threaten the biotic and abiotic components of the ecosystem. To address both the energy and agro-industrial waste issues, the production of clean and renewable energy sources, such as biofuels, by utilizing industrial waste as raw materials, can be a solution.
Some agro-industrial waste contains abundant amounts of lipids. This type of waste can pose environmental problems because the lipid content interferes with waste processing and management processes. Biological processes in waste treatment are greatly influenced by the concentration of oil and fat, particularly due to the formation of a layer that covers the surface of the wastewater. This oil and fat layer can decrease the rate of oxygen transfer in aerobic treatment processes (Prasad & Manjunath, 2011). Therefore, the disposal of lipid in the form of oil and fat in wastewater is crucial. The common physical and chemical methods currently used to remove oil and fat are inadequate, expensive, and can cause environmental pollution. As a green alternative, converting lipid-rich waste into biofuel by employing lipase-producing microbial cells as a means of waste processing and valorization can be implemented (Alves et al., 2019; Basheer et al., 2011; Creencia et al., 2014; Mongkolthanaruk & Dharmsthiti, 2002; Prasad & Manjunath, 2011; Sarac & Ugur, 2015; Tsuji et al., 2013; Tzirita et al., 2018).
The application of biocatalysts, such as lipase enzymes, with selective hydrolysis, esterification, and transesterification reactions, holds great promise in the processing of oily waste. The catalytic activity of lipase can aid in the synthesis of biodiesel, functional fatty acids, structural lipids, fatty acid esters, peptides, and polymers. The use of whole-cell lipase enzymes in bioapplications to replace chemical catalysts offers environmental and safety advantages (Amini et al., 2017; Liu et al., 2014; Matinja et al., 2019; Vargas et al., 2018). Lipase-producing microorganisms are readily found and abundant in soil, water, or oil- and fat-contaminated waste habitats. They are often involved in the natural biodegradation of organic materials in their habitats, in the form of microbial community systems, through specific metabolic pathways by releasing extracellular and membrane-bound lipases. Therefore, oily substrates can be converted into low molecular weight products to support cell growth and development. These lipase-producing microorganisms can be isolated and maintained under controlled laboratory conditions. Their lipase production performance can also be enhanced through optimization using multiple parameters, including specific nutrition and environmental conditions. In this regard, identifying conditions to enhance lipase production using readily available and inexpensive oil waste and characterizing lipases is always an important research topic (Navvabi et al., 2018).
Fidia Fibriana, S.Si., M.Sc. is a lecturer in the Department of Integrated Science Education at the Faculty of Mathematics and Natural Sciences, UNNES, specializing in Environmental Biotechnology. Several research studies conducted by her have been published in reputable national and international journals. Currently, the author is on a study assignment at Prince of Songkla University in Thailand.