Utilization of Clarified Butter Sediment Waste as a Feedstock for Cost-Effective Production of Biodiesel

Abstract

The rising demand and cost of fossil fuels (diesel and gasoline), together with the need for sustainable, alternative, and renewable energy sources have increased the interest for biomass-based fuels such as biodiesel. Among renewable sources of biofuels, biodiesel is particularly attractive as it can be used in conventional diesel engines without any modification. Oleaginous yeasts are excellent oil producers that can grow easily on various types of hydrophilic and hydrophobic waste streams that are used as feedstock for single cell oils and subsequently biodiesel production. In this study, cultivation of Rhodosporidium kratochvilovae on a hydrophobic waste (clarified butter sediment waste medium (CBM)) resulted in considerably high lipid accumulation (70.74% w/w). Maximum cell dry weight and total lipid production were 15.52 g/L and 10.98 g/L, respectively, following cultivation in CBM for 144 h. Neutral lipids were found to accumulate in the lipid bodies of cells, as visualized by BODIPY staining and fluorescence microscopy. Cells grown in CBM showed large and dispersed lipid droplets in the intracellular compartment. The fatty acid profile of biodiesel obtained after transesterification was analyzed by gas chromatography-mass spectrometry (GC–MS), while its quality was determined to comply with ASTM 6751 and EN 14214 international standards. Hence, clarified sediment waste can be exploited as a cost-effective renewable feedstock for biodiesel production.

An Overview of Potential Oleaginous Microorganisms and Their Role in Biodiesel and Omega-3 Fatty Acid-Based Industries

“…Cassia fistula L. fruit pulp 53.18 [42] Hemp seed aqueous extract 55.56 [44] Phenol 1 g/L + Glucose (7%) 64.92 [120] Hydrophobic waste (clarified butter sediment waste medium 70.74 [7] Trichosporon fermentans CICC 1368 pre-treated waste sweet potato vines under simultaneous saccharification and fermentation (SSF) [121] Rhodosporidium toruloides Brewers' spent grain [45] Lipomyces starkeyi Xylose and glucose [122] Rhodotorula glutinis Monosodium glutamate with glucose [123] Cryptococcus…”

“…Yarrowia lipolytica is considered as a model oleaginous microorganism to understand the mechanisms behind the uptake of hydrophobic substrates [205]. Some other oleaginous yeasts such as Cryptococcus, Rhodosporidium, Geotrichum, and Trichosporon have also been explored to cultivate on hydrophobic substrates [7,82]. They can assimilate free fatty acids, TAGs, and alkanes with the help of several multigene families that contribute to the catabolic and metabolic route to degrade a wide range of hydrophobic substrates [35].…”

“…The use of biodiesel is a sustainable approach to protect the atmosphere from CO 2 emissions, as well as to play an important role in global climate issues, as it leads to the reduction of greenhouse gases [6]. The use of oils derived from edible resources for large-scale biodiesel production is not a sustainable practice owing to high demands in the food sector [7]. A search for novel non-edible resources is necessary to meet this requirement.…”

“…A search for novel non-edible resources is necessary to meet this requirement. The oils from non-edible crops, waste cooking oils from food industries, and animal tallow are the other feedstock for biodiesel production that can reduce the feedstock costs [7]. However, the oils derived from waste cooking oil or other waste sources need some refinement before consideration as feedstock for biofuel production [8][9][10][11].…”

Optimization of Cerbera manghas Biodiesel Production Using Artificial Neural Networks Integrated with Ant Colony Optimization

“…The renewable energy that is easiest to handle is biofuel, which has no storage problem and is easily transported. One alternative source of energy is biodiesel, which is an alternative fuel that can be produced from a variety of feedstock, including edible and non-edible plant-based oils, animal fats, and even waste cooking oils [13][14][15]. The possibilities of biodiesels are endless-the physicochemical properties of these fuels can be tweaked by making judicious selection on the types of feedstock and the types of processes used for biodiesel production (e.g., degumming, esterification, neutralization, transesterification, and purification), by blending biodiesels with other types of biodiesels or fuels such as bioethanol and diesel, or even by optimizing the process conditions of biodiesel production.…”