Sustainable production of bio-crude oil via hydrothermal liquefaction of symbiotically grown biomass of microalgae-bacteria coupled with effective wastewater treatment

Abstract

The study demonstrates a sustainable process for production of bio-crude oil via hydrothermal liquefaction of microbial biomass generated through co-cultivation of microalgae and bacteria coupled with wastewater remediation. Biomass concentration and wastewater treatment efficiency of a tertiary consortium (two microalgae and two bacteria) was evaluated on four different wastewater samples. Total biomass concentration, total nitrogen and COD removal efficiency was found to be 3.17 g L−1, 99.95% and 95.16% respectively when consortium was grown using paper industry wastewater in a photobioreactor under batch mode. Biomass concentration was enhanced to 4.1 g L−1 through intermittent feeding of nitrogen source and phosphate. GC-MS and FTIR analysis of bio-crude oil indicates abundance of the hydrocarbon fraction and in turn, better oil quality. Maximum distillate fraction of 30.62% lies within the boiling point range of 200–300 °C depicting suitability of the bio-crude oil for conversion into diesel oil, jet fuel and fuel for stoves.

Photoautotrophs–Bacteria Co-Cultures: Advances, Challenges and Applications

“…Another fascinating study has been proposed by Goswami and colleagues, which highlighted the possibility to obtain a sustainable process for production of bio-crude oil via hydrothermal liquefaction of biomass generated by the co-cultivation of microalgae and bacteria coupled with wastewater remediation [98]. GC-MS and FTIR experiments on bio-crude oil was carried, and a great quantity of the hydrocarbon fraction was observed, as well as a high oil quality.…”

Biocrude Oil Production by Integrating Microalgae Polyculture and Wastewater Treatment: Novel Proposal on the Use of Deep Water-Depth Polyculture of Mixotrophic Microalgae

“…Effluent quality of HRAP system compared with conventional wastewater treatment ponds in New Zealand (Integrated Tables 1 and 2 in Craggs et al [18]). The polyculture of native algal communities has been used for algae biomass production and wastewater treatment in open ponds and bioreactors (Table 3) [14,[16][17][18][19][26][27][28][76][77][78][79][80][81][82][83]. However, there is little information on the compositional dynamics of the native algal community in polyculture.…”

“…Table 3 shows that polycultures of algae using sewage result in an HTL biocrude yield and quality [16,27,70,71,74,78,82,83] that matches the average monoculture. However, Goswami et al [83] reported that the biocrude-oil yield obtained from algae-bacteria consortium is 39% lower than that of mixed microalgae culture [76]. They suggested that such an inferior yield might be due to the un-optimized process parameters and quality of the biomass stocks [83].…”

“…It has been reported that the biocrude-oil yields and compositions obtained through HTL for numerous monoalgal-species are 18% to 87.2% in yield, 5.9% to 36.5% in ash content, 0.9% to 9.8% in N content, and 0.18% to 1.4% in sulfur content (except for Porphyridium, growing in high sulfur conditions at hot springs) [4,127]. Table 3 shows that polycultures of algae using sewage result in an HTL biocrude yield and quality [16,27,70,71,74,78,82,83] that matches the average monoculture. However, Goswami et al [83] reported that the biocrude-oil yield obtained from algae-bacteria consortium is 39% lower than that of mixed microalgae culture [76].…”

“…However, Goswami et al [83] reported that the biocrude-oil yield obtained from algae-bacteria consortium is 39% lower than that of mixed microalgae culture [76]. They suggested that such an inferior yield might be due to the un-optimized process parameters and quality of the biomass stocks [83].…”