A safe and sustainable bacterial cellulose nanofiber separator for lithium rechargeable batteries

Abstract

Bacterial cellulose nanofiber (BCNF) with high thermal stability produced by an ecofriendly process has emerged as a promising solution to realize safe and sustainable materials in the large-scale battery. However, an understanding of the actual thermal behavior of the BCNF in the full-cell battery has been lacking, and the yield is still limited for commercialization. Here, we report the entire process of BCNF production and battery manufacture. We systematically constructed a strain with the highest yield (31.5%) by increasing metabolic flux and improved safety by introducing a Lewis base to overcome thermochemical degradation in the battery. This report will open ways of exploiting the BCNF as a “single-layer” separator, a good alternative to the existing chemical-derived one, and thus can greatly contribute to solving the environmental and safety issues.

Towards control of cellulose biosynthesis by Komagataeibacter using systems-level and strain engineering strategies: current progress and perspectives

“…Heterologous overexpression of two of these targets, glucose-6-phosphate isomerase (pgi) and phosphogluconate dehydrogenase (gnd) brought enhanced BNC production, which was 2-fold for the strain overexpressing the E. coli pgi gene. In another study of this team, exploiting this GEM and through simulated FBA, it was found that the inclusion of a reaction catalysed by phosphofructokinase (pfkA), which is absent in the Komagataeibacter spp., improves cellulose production rate and specific growth rate (discussed later; Gwon et al 2019).…”

“…In both studies, the observed increase of cellulose production yield by the VHb+ strains was in the range of 1.5-to 1.7-fold. A more recent study involving K. xylinus DSM 2325 strain has shown that the reduction of gluconic acid production can be achieved through manipulation of regulatory proteins, besides the direct catabolic enzymes (Gwon et al 2019). This study generated a strain with reduced gluconic acid synthesis yield (39.2% in the mutant and 64.8% of glucose in the parental strain) after introduction of an additional copy of the crp (Crp/Fnr) gene, expressed from a plasmid, under the tac promoter control.…”

“…Induction of gene disruption through a homologous recombination was commonly performed with the use of non-replicating plasmid disruption cassette carriers, such as pUC19, pT7Blue, pET14 or pHSG399 (Table 4 ). At present, one can expect intensification of genetic engineering of different Komagataeibacter strains due to the progress in the application of three new vector backbones for endogenous and heterologous gene expression, namely pTI99, pTSa and pSEVA331Bb (Fang et al 2015 ; Florea et al 2016 ; Jacek et al 2018 , 2019b ; Gwon et al 2019 ). Moreover, the performance of various promoters, ribosome binding sites (RBS) and terminators has been characterised in the first two studies applying synthetic biology tools in Komagataeibacter hosts (Florea et al 2016 ; Teh et al 2019 ).…”

“…Genetic modification of the Komagataeibacter strains has been used to generate a few industrially relevant mutant strains with improved cellulose productivity. These improvements have been achieved either through metabolic pathway modulation (Shigematsu et al 2005 ; Kuo et al 2015 ; Gwon et al 2019 ) or heterologous gene expression (Setyawati et al 2007 ; Liu et al 2018b ; Jang et al 2019 ).…”

Enhanced Production of Bacterial Cellulose in Komagataeibacter xylinus Via Tuning of Biosynthesis Genes with Synthetic RBS

“…BC has outstanding properties, such as high water retention value, surface area, crystallinity, biodegradability, biocompatibility, and high purity due to the absence of lignin and hemicellulose [3][4][5][6]. Due to these properties, BC has potential applications in the biomedical, cosmetic, automotive, packaging, health food, electrical, and sensor industries, with a rapidly increasing commercial value [7][8][9].…”