Characterisation of bio-oil extracted from microalgae Botryococcus sp. biomass grown in domestic and food processing wastewaters for valuable hydrocarbon production

Microalgae cultivation for biofuels feedstock and value-added chemicals is a sustainable approach to renewable energy generation development. This study aims to establish a detailed hydrocarbon profile for freshwater green microalgae oil extracted from local Botryococcus sp. biomass cultivated using domestic wastewater (DW) and food processing wastewater (FW). The cultivation experiment was conducted using an enclosed photobioreactor in triplicate for 18 days under an outdoor condition. Microalgae bio-oil was extracted by employing the Soxhlet extraction method (EPA 9071B), and the various potential hydrocarbon characterisations were obtained using GC-MS analysis. The extracted microalgae oil content was higher when Botryococcus sp. was cultivated in DW (70.7%) compared to FW (53.1%) as a culture medium. The GC-MS analysis found that Phenol, 2,4-bis(1,1-dimethylethyl) -(C14H22O), contributed the highest peak percentage (29.6%) of the total hydrocarbon compounds when utilised DW as a culture medium. Meanwhile, Hexadecenoic acid, methyl ester (C17H34O2) was found as the major compound revealed from Botryococcus sp. that grew in FW with 41% of peak total hydrocarbon. Both wastewater types show potential for cultivating Botryococcus sp. for hydrocarbon production and may serve as environmentally friendly feedstocks for biofuels and chemical ingredients in many industries.

Automated summary

This study aimed to establish a detailed hydrocarbon profile for freshwater green microalgae oil cultivated using domestic wastewater and food processing wastewater. The results showed that the type of wastewater had an impact on the quantity and composition of microalgae oil, indicating the potential of wastewater cultivation for petroleum alternative energy and chemical ingredients.