Polycationic surfaces promote whole-cell immobilization and induce micro-granulation of Clostridium saccharoperbutylacetonicum N1-4 for enhanced biobutanol production

Authors: JIMÉNEZ-BONILLA, PABLO - Auburn University; ZHANG, JIE - Auburn University; WANG, YIFEN - Auburn University; BLERSCH, DAVID - Auburn University; ESTELA DE-BASHAN, LUZ - Auburn University; GUO, LIANG - Ocean University Of China; LI, XIAO - Auburn University; Zhang, Dunhua; WANG, YI - Auburn University

Submitted to: ACS Applied Materials and Interfaces
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2022
Publication Date: 10/25/2022
Citation: Jiménez-Bonilla, P., Zhang, J., Wang, Y., Blersch, D., Estela De-Bashan, L., Guo, L., Li, X., Zhang, D., Wang, Y. 2022. Polycationic surfaces promote whole-cell immobilization and induce micro-granulation of Clostridium saccharoperbutylacetonicum N1-4 for enhanced biobutanol production. ACS Applied Materials and Interfaces. 2022(14):49555-49567. https://doi.org/10.1021/acsami.2c14888.
DOI: https://doi.org/10.1021/acsami.2c14888

Interpretive Summary: N-butanol (butanol hereafter) could be used as a fuel with many advantages over ethanol or as a chemical with numerous industrial applications. Currently, industrial butanol is primarily produced through the petrochemical route. With the concerns about depletion of natural resources and environmental deterioration associated with the consumption of fossil fuels, people are seeking alternative strategies to produce fuels and chemicals from renewable resources. despite tremendous research efforts in the past, clostridial butanol production is still not economically viable and uncompetitive with the traditional petrochemical route. In this study, we investigated the utilization of insoluble chitosan for immobilization of Clostridium saccharoperbutylacetonicum N1-4, a hyper-butanolproducing strain, to improve the cell density and butanol production. We also tried to elucidate the correlation between the fermentation performance and the chemical properties of the carrier materials. This work provides evidence that chitosan as the carrier material enhanced cell growth and fermentation performance through double mechanisms of “cell adsorption immobilization” and “induced cell self-aggregation”. The methods developed in this study can be applied to many other cellulosic or lignocellulosic materials for various application purposed.

Technical Abstract: Immobilization is a common strategy used to protect microbial cells to improve the performance of bioprocesses. However, the interaction mechanism between the cells and the immobilization material is generally poorly understood. In this study, we employed natural polysaccharide-based materials as immobilization carriers for clostridial fermentation in an attempt to enhance the production of butanol (a valuable biofuel/biochemical but highly toxic to the host cells) and meanwhile elucidate the interaction mechanisms related to immobilization. The utilization of chitosan powder as the immobilization carrier enhanced butanol productivity by 97% in the fermentation with Clostridium saccharoperbutylacetonicum N1-4 and improved butanol titer by 21% in the fermentation with Clostridium beijerinckii NCIMB 8052. Additionally, analogue derivatives using microcrystalline cellulose (MCC) and cotton cationized on the surface with 3-chloro-2-hydroxypropyltrymethylammonium (CHPTA) and 2-chloro-N,Ndiethylaminoethyl chloride (DEAEC) were prepared and used as immobilization carriers for similar fermentation conditions. The CHPTA derivatives showed slightly increased production of butanol and total solvent with C. saccharoperbutylacetonicum. Overall, our results indicated that the interaction between the cell and the carrier material occurs through a double mechanism involving adsorption immobilization and induced aggregation. This work provides insights concerning the effects of the chemical properties of the carrier material (such as the cation density and surface area) on fermentation performance, enabling a better understanding of the interaction between bacterial cells and the cationic materials. The derivatization strategies employed in this study can be applied to most cellulosic materials to modulate the properties and enhance the interaction between the cell and the carrier material for immobilization, thus improving the bioprocess performance.