Thermophilic bio-electro CO₂ recycling into organic compounds

Abstract

Many industrial combustion processes produce carbon dioxide (CO2) at high temperature, which may be electrically recycled into valuable chemicals using microorganisms as catalysts.

Carbon dioxide to bio-oil in a bioelectrochemical system-assisted microalgae biorefinery process

“…An increase in acetate production associated with augmented nutrient availability was already reported by Rovira-Alsina and co-workers. 29 At day 80 the maximum acetic acid production rate (289 mg L À1 d À1 ) and its highest concentration in the whole experimentation were obtained in HT1 (13 063 mg L À1 ; Table 2). Comparable values in terms of concentration have seldom been reported in the literature.…”

“…Both cathodes were inoculated with 20 mL (10% v/ v) of electroactive inoculum from a parent thermophilic (50 C) MES reactor. 29 The experiment was conducted at 25 AE 3 C.…”

“…The concentrations of dissolved H 2 and CO 2 were calculated according to Henry's law at 25 C. Both MES reactors were ushed and saturated with CO 2 aer the sampling phase, assuming conditions of CO 2 saturation and absence of H 2 in the liquid phase aer each feeding. Coulombic efficiency (CE) was calculated according to Rovira-Alsina et al 29 Carbon conversion efficiency was nally calculated according to the maximum acetate production rate achieved. The nal product (bio-oil) conversion efficiency from CO 2 was calculated according to the amount of acetate fed to the microalgae, and the ratio between the weight of the dry sample collected and the weight of the oil sample obtained at the end of the extraction procedure.…”

“…The biocathodes inoculated with 20 mL of a parent MES operated under thermophilic conditions (50 C) 29 produced acetate from carbon dioxide (max production rate 28 g m À2 d À1 , with a maximum titre of 5250 mg L À1 ). Adaptation to mesophilic conditions (25 C) lasted 25 days, when low VFA production was observed and, once stabilized, modied ATCC1754 PETC medium was replaced by BG-11 in the anode (Section 2.2).…”

Waste C1 Gases as Alternatives to Pure CO2 Improved the Microbial Electrosynthesis of C4 and C6 Carboxylates

“…In light of the practical application of MES for the bioconversion of CO-rich gas streams, the high temperature and the impurities of waste gas are also expected to affect the performance. Recently, the thermophilic community was successfully enriched with the temperature of MES controlled at 50 °C and even 60 °C, which could also decrease the risk of contamination. , Among these impurities, the H 2 could serve as additional electron donors, while the inert CH 4 could be collected with the gaseous products. Other impurities such as H 2 S and NH 3 , which are toxic to microorganisms, however, are generally produced with very low concentration. , …”