Biodiesel Production From Lignocellulosic Biomass Using Oleaginous Microbes: Prospects for Integrated Biofuel Production.

Anjani Devi Chintagunta,Anuj K Chandel,N S Sampath Kumar,Gaetano Zuccaro,Mahesh Kumar,Vijay Kumar Garlapati,Pablo D Postemsky,Jesus Simal-Gandara,S P Jeevan Kumar

doi:10.3389/fmicb.2021.658284

Abstract

Biodiesel is an eco-friendly, renewable, and potential liquid biofuel mitigating greenhouse gas emissions. Biodiesel has been produced initially from vegetable oils, non-edible oils, and waste oils. However, these feedstocks have several disadvantages such as requirement of land and labor and remain expensive. Similarly, in reference to waste oils, the feedstock content is succinct in supply and unable to meet the demand. Recent studies demonstrated utilization of lignocellulosic substrates for biodiesel production using oleaginous microorganisms. These microbes accumulate higher lipid content under stress conditions, whose lipid composition is similar to vegetable oils. In this paper, feedstocks used for biodiesel production such as vegetable oils, non-edible oils, oleaginous microalgae, fungi, yeast, and bacteria have been illustrated. Thereafter, steps enumerated in biodiesel production from lignocellulosic substrates through pretreatment, saccharification and oleaginous microbe-mediated fermentation, lipid extraction, transesterification, and purification of biodiesel are discussed. Besides, the importance of metabolic engineering in ensuring biofuels and biorefinery and a brief note on integration of liquid biofuels have been included that have significant importance in terms of circular economy aspects.

Highlights

Biodiesel is one of the prospective renewable fuels produced from different plant oils, animal fats, waste oils, and microbial lipids (Banerjee et al, 2019a; Kumar et al, 2020c)
Non-edible vegetable oil is a better alternative but has some constraints in the path to be suitable for biodiesel feedstock such as long growing period, requirement of ample land for sufficient production, and variation in lipid quality upon changing the plant species, climate, season, and geography (Kumar et al, 2020a)
Biodiesel production from lignocellulosic biomass (LCB) consists of four important steps such as delignification, saccharification, fermentation with Oleaginous microorganisms (OMs) for higher lipid synthesis, and subsequent conversion to transesterification (Zhao et al, 2008; Kumar et al, 2017c)

Summary

Introduction

Biodiesel is one of the prospective renewable fuels produced from different plant oils, animal fats, waste oils, and microbial lipids (Banerjee et al, 2019a; Kumar et al, 2020c). Oleaginous microorganisms (OMs) are capable of utilizing inexpensive feedstocks [agro-residues, lignocellulosic substrates (LCSs)] and waste substrates for higher lipid accumulation (Kumar et al, 2020d). Various feedstocks have been explored for biodiesel production, which can be categorized into four groups: vegetable oil (edible and non-edible), waste or recycled oil, animal fat, and OMs (Kumar et al, 2019).

Results

Conclusion