Bioprocesses for the Biodiesel Production from Waste Oils and Valorization of Glycerol

Abstract

The environmental context causes the use of renewable energy to increase, with the aim of finding alternatives to fossil-based products such as fuels. Biodiesel, an alternative to diesel, is now a well-developed solution, and its production from renewable resources makes it perfectly suitable in the environmental context. In addition, it is biodegradable, non-toxic and has low greenhouse gas emissions: reduced about 85% compared to diesel. However, the feedstock used to produce biodiesel competes with agriculture and the application of chemical reactions is not advantageous with a “green” process. Therefore, this review focuses only on bioprocesses currently taking an important place in the production of biodiesel and allow high yields, above 90%, and with very few produced impurities. In addition, the use of waste oils as feedstock, which now accounts for 10% of feedstocks used in the production of biodiesel, avoids competition with agriculture. To present a complete life-cycle of oils in this review, a second part will focus on the valorization of the biodiesel by-product, glycerol. About 10% of glycerol is generated during the production of biodiesel, so it should be recovered to high value-added products, always based on bioprocesses. This review will also present existing techniques to extract and purify glycerol. In the end, from the collection of feedstocks to the production of CO2 during the combustion of biodiesel, this review presents the steps using the “greener” possible processes.

Evaluation on the Large Scale Glycerol Production from Used Cooking Oil using SuperPro Designer Simulator

“…For this purpose, a granular adsorption on activated charcoal (GAC adsorption) was proposed. This alternative is e cient to remove excess water attenuating colour of glycerol (Decarpigny et al, 2022). Lastly, the high purity glycerol was stored and is now poised to be transformed into high-value-added products.…”

“…In the second stage of separation, the glycerol recovery was conducted using vacuum distillation. Distillation is generally carried out to remove excess water, salt content and matter organic non -glycerol based on the boiling point (Decarpigny et al, 2022;Jariah et al, 2021). In distillation column, glycerol was separated from water where water was removed from top while glycerol was removed from bottom.…”

Glycerol Electro-Oxidation in Alkaline Medium with Pt-Fe/C Electrocatalysts Synthesized by the Polyol Method: Increased Selectivity and Activity Provided by Less Expensive Catalysts

“…Glycerol, a renewable, low-cost, and widely available compound, is a waste product from the transesterification of vegetable oils for biodiesel production—10% m/m of the products is glycerol [ 1 , 2 , 3 , 4 ]. Given that the rate of world biodiesel production is high, new applications for glycerol as a platform molecule for the chemical industry must be found [ 2 , 3 , 4 , 5 ].…”

Optimization of the glycerol production fromDunaliella tertiolectaandDunaliellaisolates

“…The application in the field of pharmacology and food requires a glycerol purity greater than 99.7%. However, commonly used purification methods of the biofuel-derived glycerol do not achieve the needed purity [22]. Additionally, bio-fuel production utilizes enormous agricultural areas necessary to nourish the world population [23, 24].…”

“…Therefore, a sustainable and less area-intensive production process for the extensively required raw material glycerol is of great importance [18, 25]. Used cooking oil might be a sustainable alternative for the bio-fuel and glycerol production [26], but also does not reach a glycerol purify higher than 99.7% [22]. Furthermore, the resulting glycerol is not necessarily halal, which is needed for pharmaceutical and food application with halal quality [27].…”