Comparative Studies of Oleaginous Fungal Strains (Mucor circinelloides and Trichoderma reesei) for Effective Wastewater Treatment and Bio-Oil Production

Biological wastewater treatment typically requires the use of bacteria for degradation of carbonaceous and nitrogenous compounds present in wastewater. The high lipid containing biomass can be used to extract oil and the contents can be termed as bio-oil (or biodiesel or myco-diesel after transesterification). The separate experiments were conducted on actual wastewater samples with 5% v/v inoculum of Mucor circinelloides MTCC1297 and Trichoderma reesei NCIM992 strains. The observed reductions in chemical oxygen demand (COD) were 88.72% and 86.75% in 96 hrs and the observed substrate based biomass yields were 0.21 mg VSS/mg COD and 0.22 mg VSS/mg COD for M. circinelloides reactor and for T. reesei reactor, respectively. The resulted bio-oil production from wastewater treatment by M. circinelloides and T. reesei reactors was 142.2 mg/L and 74.1 mg/L, whereas biomass containing bio-oil contents (%w/w) were 22.11% and 9.82%, respectively. In this experiment, the fungal wastewater treatment was also compared with conventional bacterial process with respect to specific growth rate, biomass production, and oil content. This study suggests that wastewater can be used as a potential feedstock for bio-oil production with the use of oleaginous fungal strains and which could be a possible route of waste to energy.