Bioproduction of benzaldehyde in a solid–liquid two-phase partitioning bioreactor using Pichia pastoris

Abstract

The bioproduction of benzaldehyde from benzyl alcohol using Pichia pastoris was examined in a solid-liquid two-phase partitioning bioreactor (TPPB) to reduce substrate and product inhibition. Rational polymer selection identified Elvax 40W as an effective sequestering phase, possessing partition coefficients for benzyl alcohol and benzaldehyde of 3.5 and 35.4, respectively. The use of Elvax 40W increased the overall mass of benzaldehyde produced by approx. 300% in a 5 l bioreactor, relative to a single phase biotransformation. The two-phase system had a molar yield of 0.99, indicating that only minor losses occurred. These results provide a promising starting point for solid-liquid TPPBs to enhance benzaldehyde production, and suggest that multiple, targeted polymers may provide relief for transformations characterized by multiple inhibitory substrates/product/by-products.

A first principles approach to identifying polymers for use in two‐phase partitioning bioreactors

“…For example, the relative absorption of benzaldehyde (solubility parameter, δ = 21.4 MPa 1/2 ) and benzyl alcohol (δ = 23.8 MPa 1/2 ) differs drastically among different polymers. 13 In this case, the vinylacetaterich (δ ≈ 18.8 MPa 1/2 ) and butadiene-rich (δ ≈ 17.0 MPa 1/2 ) polymers tested in the study absorbed significantly less benzyl alcohol relative to benzaldehyde than the butylene oxide-rich polymer (δ ≈ 19.4 MPa 1/2 ), a result of the larger difference between the polymers' solubility parameters and that of benzyl alcohol. Selecting a polymer whose solubility parameter lies closer to the target molecule to be absorbed provides control over multiple compounds' aqueous concentrations, demonstrating a basis for selectivity between similar target molecules.…”

“…13 Our aim was to gain insight into these findings by establishing a deeper understanding of the factors influencing polymer absorption through a systematic analysis of polymer properties and their effect on target molecule absorption.…”

Microbial Engineering for Aldehyde Synthesis

“…If control of selective metabolite transport through the protein shells were achieved, then the engineering of these compartments for biosynthesis of new aldehyde-derived products might aid in limiting the pool size of free aldehyde intermediates (90). Independently of the mode of toxicity, in situ separation using stripping (91), two-phase systems (92), or selective resins (93) may result in increased production of aldehydes as end products. Many aldehydes of interest are hydrophobic and volatile, which are properties that aid separation from water-based fermentation processes.…”

Comparing in situ removal strategies for improving styrene bioproduction

“…Examples of successful approaches for the in situ recovery of inhibitory biomolecules include solvent extraction [20,23,24], adsorption [25][26][27], gas stripping [28], vacuum stripping [29], and membrane pervaporation [30,31]. Meanwhile, whereas in situ recovery strategies have been demonstrated as effective for improving the bioproduction of other aromatic compounds (e.g., 2-phenylethanol, phydroxystyrene, (S)-styrene oxide, and benzaldehyde) [32][33][34][35][36][37], their application to bio-derived styrene has not yet been reported. Moreover, whereas said prior studies have predominantly focused on single step biotransformations, the alternative focus here on de novo biosynthesis directly from renewable glucose presents new challenges.…”