New biofuel alternatives: integrating waste management and single cell oil production.

Elia Martínez,Xiomar Gómez,Fernando González-Andrés,Vijaya Raghavan

doi:10.3390/ijms16059385

Abstract

Concerns about greenhouse gas emissions have increased research efforts into alternatives in bio-based processes. With regard to transport fuel, bioethanol and biodiesel are still the main biofuels used. It is expected that future production of these biofuels will be based on processes using either non-food competing biomasses, or characterised by low CO2 emissions. Many microorganisms, such as microalgae, yeast, bacteria and fungi, have the ability to accumulate oils under special culture conditions. Microbial oils might become one of the potential feed-stocks for biodiesel production in the near future. The use of these oils is currently under extensive research in order to reduce production costs associated with the fermentation process, which is a crucial factor to increase economic feasibility. An important way to reduce processing costs is the use of wastes as carbon sources. The aim of the present review is to describe the main aspects related to the use of different oleaginous microorganisms for lipid production and their performance when using bio-wastes. The possibilities for combining hydrogen (H2) and lipid production are also explored in an attempt for improving the economic feasibility of the process.

Highlights

In recent decades, oil prices have been experiencing an increasing trend
The present behaviour of the market is resulting in lower oil prices, this may be considered as a temporary situation that may sooner or later come to an end
The aim of the present review is to describe the main aspects related to the use of different oleaginous microorganisms for lipid production and their performance when using low-cost carbon substrates

Summary

Introduction

Oil prices have been experiencing an increasing trend. the present behaviour of the market is resulting in lower oil prices, this may be considered as a temporary situation that may sooner or later come to an end. These fuels may be defined based on the conversion technologies used, which are still in the research and development (R&D), pilot or demonstration phases, and are commonly referred to as second- or third-generation biofuels [1] In this sense, it is expected that in the near future the production of bioethanol and biodiesel—as well as other advanced biofuels—will be based on processes characterised by low CO2 emissions and by the use of organic materials that are different to those traditionally associated with the food-supply chain. More than 95% of biodiesel production feedstocks come from edible oils, which exert a lot of pressure on the cost of raw materials It is a cause of deforestation in some countries due to the increase in agricultural land required [4,5].

Lipid-Accumulating Organisms

De Novo Lipid Accumulation

Ex Novo Lipid Accumulation

Improving Lipid Production from Wastes

Findings

Conclusions