Economic optimization of in situ extraction of inhibitors in acetone-ethanol-butanol (ABE) fermentation from lignocellulose

Abstract

The inhibitors produced in the pretreatment (phenolics, furans, and organic acids) as well as in the fermentation (butanol and organic acids) limit acetone, butanol, and ethanol (ABE) production from lignocellulose. To reduce their negative impact on the fermentation, a process involving simultaneous saccharification, ABE fermentation, and detoxification by liquid-liquid extraction was proposed and economically optimized. Although several extractants may be used to reduce butanol toxicity increasing the reactor performance, simultaneous detoxification of inhibitors from pretreatment (IFP) is difficult due to their high boiling point. Hence, the simultaneous detoxification system was evaluated using the biocompatible extractant: oleyl alcohol (boiling point of ~350 °C). Given that oleyl alcohol and IFP have a high boiling point, a heat-integrated distillation system with low-pressure columns was proposed to reduce the energy requirements of the purification of IFP and products from the fermentation. The simulations were performed rigorously in Aspen Plus ® and Matlab ® at different concentrations of IFP. Although IFP and butyric acid production become feasible ABE production by SSF-E at concentrations of IFP between 13.5 and 30 g/l, the energy requirements were between 1.2-and 2.4-fold higher than that for IFP concentrations of 9 g/l, respectively.

Production of butanol from lignocellulosic biomass: recent advances, challenges, and prospects

“…In general, levels of inhibitors and fermentable sugars in hydrolysates are dependent on the feedstock and the conditions of pretreatment and hydrolysis processes. 106 Thus, several strategies have been developed to counteract inhibition problems, including (1) selecting less recalcitrant feedstocks; (2) utilising mild pretreatment conditions; (3) biological hydrolysis of hemicelluloses with specific enzymes, or co-culture of microorganisms producing hydrolysing enzymes 107 to effectively decrease the formation of inhibitors (but this can increase several incumbent costs); 108 (4) combining pretreatment, hydrolysis, fermentation and product recovery into a single consolidated process; 109 (5) integrating several detoxification methods, such as electrodialysis, 110 liming/overlimiting, 111 activated carbon/charcoal, 112 in situ extraction with oleyl alcohol, 113 and filtration or centrifugation, and resin treatments 114 to remove solids and undissolved lignin in lignocellulosic hydrolysates. However, although these inhibitors can be effectively removed during the detoxification process, 115 partial fermentable sugars are also removed from lignocellulosic hydrolysates, 116 making the detoxification process impractical for commercial application.…”

Revisión de las tecnologías avanzadas para la producción de butanol: un biocombustible alternativo.

“…Un alto coeficiente de reparto es deseado ya que se debe usar una menor cantidad de solvente para alcanzar el nivel de separación deseado. Adicionalmente, altos coeficientes de recuperación permiten reducir los requerimientos energéticos en la recuperación del extractante en el sistema de destilación [88]. Por otro lado, altas selectividades reducen el contenido de agua la fase orgánica y se pueden alcanzar mayores concentraciones de producto.…”

“…El alcohol oleico es uno de los más usados por su biocompatibilidad en sistemas de reacción in situ, pese a sus coeficientes de reparto y selectividades intermedios. Una ventaja adicional del alcohol oleico es su capacidad de extraer inhibidores generados en el petratamiento físico-químico del material lignocelulósico [88]. Con una purificación final por destilación, este sistema con detoxificación simultanea permite generar un valor agregado adicional, debió a la producción simultanea de furfurol y compuestos fenólicos.…”

Modeling the Effect of Temperature on Ethanol Fermentation Using Saccharomyces Cerevisiae CSI-1 by Genetic Programming

“…Modeling has been employed to elucidate cell growth in relation to temperature (Abunde et al, 2019;Nor-Khaizura et al, 2019;Pereira et al, 2020). However, the outcome of simulation and optimization tools heavily relies on the quality of the mathematical model (Carrillo-Ahumada et al, 2020;Castillo-Santos et al, 2017;Darvishi et al, 2020;Díaz &Tost, 2018;Goelzer et al, 2009;Hebing et al, 2020;Jorayev et al, 2022;Meng et al, 2021;Müller et al, 2020;Rodríguez-Mariano et al, 2015;Salmi et al, 2021;Torralba-Morales et al, 2020;Vignesh & Chandraraj, 2021;Wu et al, 2015). Typically, fermentations rely on ideal laboratory conditions (e.g., synthetic media, stirring devices, heating modes), and it is preferable to consider industrial processes (real fermentation media, steady state, etc.)…”