A novelin situgas stripping‐pervaporation process integrated with acetone‐butanol‐ethanol fermentation for hyper n‐butanol production

Abstract

Butanol is considered as an advanced biofuel, the development of which is restricted by the intensive energy consumption of product recovery. A novel two-stage gas stripping-pervaporation process integrated with acetone-butanol-ethanol (ABE) fermentation was developed for butanol recovery, with gas stripping as the first-stage and pervaporation as the second-stage using the carbon nanotubes (CNTs) filled polydimethylsiloxane (PDMS) mixed matrix membrane (MMM). Compared to batch fermentation without butanol recovery, more ABE (27.5 g/L acetone, 75.5 g/L butanol, 7.0 g/L ethanol vs. 7.9 g/L acetone, 16.2 g/L butanol, 1.4 g/L ethanol) were produced in the fed-batch fermentation, with a higher butanol productivity (0.34 g/L · h vs. 0.30 g/L · h) due to reduced butanol inhibition by butanol recovery. The first-stage gas stripping produced a condensate containing 155.6 g/L butanol (199.9 g/L ABE), which after phase separation formed an organic phase containing 610.8 g/L butanol (656.1 g/L ABE) and an aqueous phase containing 85.6 g/L butanol (129.7 g/L ABE). Fed with the aqueous phase of the condensate from first-stage gas stripping, the second-stage pervaporation using the CNTs-PDMS MMM produced a condensate containing 441.7 g/L butanol (593.2 g/L ABE), which after mixing with the organic phase from gas stripping gave a highly concentrated product containing 521.3 g/L butanol (622.9 g/L ABE). The outstanding performance of CNTs-PDMS MMM can be attributed to the hydrophobic CNTs giving an alternative route for mass transport through the inner tubes or along the smooth surface of CNTs. This gas stripping-pervaporation process with less contaminated risk is thus effective in increasing butanol production and reducing energy consumption.

The advanced strategy for enhancing biobutanol production and high-efficient product recovery with reduced wastewater generation

“…In general, the tradeoff between water consumption and butanol concentration is valuable for microbial butanol production from lignocellulosic biomass. The improved butanol concentration significantly contributes to the reduced product recovery cost by conventional distillation [20, 33]. In consideration of butanol concentration, more water is preferable for providing a suitable environment for fermentation strain by completely removing inhibitory products and residual NaOH.…”

Transcriptional analysis of degenerate strain Clostridium beijerinckii DG-8052 reveals a pleiotropic response to CaCO3-associated recovery of solvent production

“…Over the past three decades, extensive research were carried out to find solutions for overcoming Clostridia strain degeneration. It was reported that addition of sodium acetate to MP2 medium could prevent degeneration in Clostridium beijerinckii NCIMB 8052 and BA101, a solvent-hyperproducing mutant derived from 80524; Recently, in hyper-butanol producing C. acetobutylicum JB200, the integrated gas stripping to remove product during fermentation was found to increase butanol productivity without culture degeneration56.…”

Moderate alkali-thermophilic ethanologenesis by locally isolated Bacillus licheniformis from Pakistan employing sugarcane bagasse: a comparative aspect of aseptic and non-aseptic fermentations

“…Gas stripping is an established product recovery technique for ABE separation [23, 48–51]. It was confirmed that ethanol intolerance was one of the reasons of growth inhibition.…”