Anaerobic fermentation of glycerol: a platform for renewable fuels and chemicals

To ensure the long-term viability of biorefineries, it is essential to go beyond the carbohydrate-based platform and develop complementing technologies capable of producing fuels and chemicals from a wide array of available materials. Glycerol, a readily available and inexpensive compound, is generated during biodiesel, oleochemical, and bioethanol production processes, making its conversion into value-added products of great interest. The high degree of reduction of carbon atoms in glycerol confers the ability to produce fuels and reduced chemicals at higher yields when compared to the use of carbohydrates. This review focuses on current engineering efforts as well as the challenges involved in the utilization of glycerol as a carbon source for the production of fuels and chemicals

Recent achievements in the production of biobased 1,3-propanediol

The increasing concerns related to the high prices and limited availability of fossil fuels have led to a remarkable growth of biodiesel industry in recent years. This, in turns resulted in the accumulation of high quantities of crude glycerol as a byproduct of the transesterification reaction. It is indeed estimated that the production of 100 kg of biodiesel results in the production of 10 kg of crude glycerol. The obtained crude glycerol byproducts could be purified and further used in several processes but this purification process is costly. The biorefinery concept i.e. the exploitation of wastes or byproducts for the obtainment of high value products has been then considered as an interesting alternative strategy for the valorization of this byproduct. In this context, several fine chemicals among which 1,3-propanediol are produced from biodiesel-derived raw glycerol feedstock . In this chapter, we report on recent achievements in the production of 1,3-propanediol from biodiesel-derived crude glycerol including a detailed literature review on the biotechnological processes developed and the strategies employed for yields improvement. The bottlenecks of these biorefinery processes are also discussed