Journal of Environmental Treatment Techniques  
2021, Volume 9, Issue 1, Pages: 280-288  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link:  
A Review on Oleaginous Microorganisms for  
Biological Wastewater Treatment: Current and  
Future Prospect  
Mohammed B. Al Rayaan 1* and, Ibrahim A. Alshayqi 2  
Department of Environmental Sciences and Engineering, King Abdullah University of Science & Technology, Thuwal, Saudi Arabia, email:  
Department of Environmental Engineering, University of Dammam, Dammam, Saudi Arabia  
Received: 09/09/2020  
Accepted: 16/11/2020  
Published: 20/03/2021  
The water scarcity issue is becoming a critical issue to the climate change, industrialization and urbanization. Prompt to the advances in  
biotechnology, Oleaginous microorganisms have been discovered and successfully applied in biological wastewater treatments, which are  
highly effective for wastewater clean-up and energy efficient lipid conversion to value-added products. This paper aims to review the recent  
advances of the application of different types of Oleaginous microorganisms (e.g. yeasts, microalgae, and fungi) as well as the advantages,  
limitations and application fields (food industry, municipal waste and chemical plant). The future prospect and challenges of Oleaginous  
microorganism that warrant in environmental settings or engineered systems are also highlighted in the review. In order to improve the  
Technology Readiness Level (TRL), the future research direction should be more focussed on the economic and environmental studies.  
Keywords: Oleaginous microorganisms; Biological wastewater treatment; Microalgae; Industrial application  
been reported for biochar production using rich in ammonia-N  
swine wastewater as source of nutrient [14]. Most importantly,  
the valorisation of Oleaginous microorganisms in low-cost  
substrates like nutrient-rich wastewaters is a circular economy  
concept that can help improve the economic feasibility of the  
wastewater treatment plants related industries with a net positive  
value. Thus, in this review, we aim to provide a comprehensive  
insight on the advances of wastewaters treatment by Oleaginous  
microorganisms which includes 1) The types of Oleaginous  
microorganisms used for biological treatment such as microalgae,  
yeast, fungi and bacteria; 2) The industrial application of  
Oleaginous microorganisms such as food, pharmaceutical and  
municipal waste industries and also; 3) The commercialization  
attractiveness and challenges of the technology.  
The fresh water demand is rapidly increasing due to  
urbanization and industrialization, and predicted to beyond than  
5% in by the year of 2025 [1]. In recent year, “wastewater  
treatment field” is becoming a hot topic in both academic and  
industrial community to eliminate both chemical and microbial  
Nevertheless, the reuse of water from treated wastewater effluents  
can pose a serios health issue due to contamination such as  
microbial pollutants, heavy metals, suspended solid and organic  
matters [3]. To date, biological treatment is well-acknowledged  
as one of the most eco-friendly and cost-effective way to remove  
those contaminants from wastewater [1, 4-8]. Notably, the use of  
Oleaginous microorganisms in biological treatment of wastewater  
is much attractive as compared with the traditional aerobic  
digestion and anaerobic digestion technologies which requires  
high-end system such as up-flow anaerobic sludge blanket  
digestion or expanded granular sludge bed digestion [9-11].  
Apart from cost-effectiveness, Oleaginous microorganisms  
can clean up the wastewaters effectively within a short period  
with valuable generation of some value-added products as shown  
in Fig. 1. For instance, Chlorella pseudolambica has been studied  
in livestock wastewater for biodiesel production [12];  
Sterigmatomyces halophilus has been applied in textile dyeing  
wastewater for bioremediation [13]; and Chlorella vulgaris has  
2 Types of Oleaginous microorganisms used for  
biological treatment of wastewaters  
Most of the studies have reported that Oleaginous  
microorganisms accumulate a high lipid content in the range of  
14-75% of their dry weight [15-20]. To date, Botryococcus  
braunii is reported as one of the richest lipid content  
microorganisms in which 74.5 % of lipid (58.8% nonpolar lipids  
and 15.7% polar lipids) can be extracted [21].  
Corresponding author: Mohammed B. Al Rayaan, Department of Environmental Sciences and Engineering, King Abdullah University of  
Science & Technology, Thuwal, Saudi Arabia, Email: