Effect of ethanol supplementation on the transcriptional landscape of bionanocellulose producer Komagataeibacter xylinus E25

Abstract

Ethanol exerts a strong positive effect on the cellulose yields from the widely exploited microbial producers of the Komagataeibacter genus. Ethanol is postulated to provide an alternative energy source, enabling effective use of glucose for cellulose biosynthesis rather than for energy acquisition. In this paper, we investigate the effect of ethanol supplementation on the global gene expression profile of Komagataeibacter xylinus E25 using RNA sequencing technology (RNA-seq). We demonstrate that when ethanol is present in the culture medium, glucose metabolism is directed towards cellulose production due to the induction of genes related to UDP-glucose formation and the repression of genes involved in glycolysis and acetan biosynthesis. Transcriptional changes in the pathways of cellulose biosynthesis and c-di-GMP metabolism are also described. The transcript level profiles suggest that Schramm-Hestrin medium supplemented with ethanol promotes bacterial growth by inducing protein biosynthesis and iron uptake. We observed downregulation of genes encoding transposases of the IS 110 family which may provide one line of evidence explaining the positive effect of ethanol supplementation on the genotypic stability of K. xylinus E25. The results of this study increase knowledge and understanding of the regulatory effects imposed by ethanol on cellulose biosynthesis, providing new opportunities for directed strain improvement, scaled-up bionanocellulose production, and wider industrial exploitation of the Komagataeibacter species as bacterial cellulose producers. Electronic supplementary material The online version of this article (10.1007/s00253-019-09904-x) contains supplementary material, which is available to authorized users.

Kinetic Study of a Bacterial Cellulose Production by Komagataeibacter Rhaeticus Using Coffee Grounds and Sugarcane Molasses

“…This solvent acts as an activator in cell growth and depending on the concentration may favor the production of bacterial cellulose 28,30 . This results in the effective use of glucose for the cellulose synthesis and not in its use for the acquisition of energy 31 . The great contribution of ethanol in the bacterial cellulose production can be seen in Figure 1, when graphically comparing the productions of biopolymer during the period from 0 to 240 h for culture media (A), (B) and (C).…”

Bacterial Nanocellulose—A Biobased Polymer for Active and Intelligent Food Packaging Applications: Recent Advances and Developments

“…Therefore, the production process remains relatively expensive, which is mainly determined by high costs of cultivation media and other growth factors [ 12 ]. The wider commercial applications of BNC, including the food and paper industry, are hampered mainly due to the price [ 59 ]. Currently, various studies are being carried out in order to improve bacterial nanocellulose production to reduce operating costs and increase biocellulose synthesis yield [ 60 ].…”

“…The choice of parameters such as pH, temperature, incubation time, dissolved oxygen content, chemical composition of medium, culture methods (agitated or stationary cultivation), and other operational conditions play the key role in bionanocellulose production [ 12 , 60 ]. It has been shown that supplementation of the defined growth media with alternative substrates (e.g., ethanol, acetic acid, lactic acid, sodium citrate, vitamins, glycerol, polymers such as carboxymethylcellulose (CMC), or agar) can improve BNC biosynthesis [ 59 , 75 , 76 , 77 , 78 , 79 , 80 ]. Molina-Ramirez et al [ 75 ] reported the growth in bacterial nanocellulose yield up to 279% by the addition of alternative energy sources, such as ethanol and acetic acid to SH medium.…”

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

“…The type II operon ( bcsII ) is probably responsible for the production of acylated cellulose due to the presence of an acyltransferase gene within its structure (Umeda et al 1999 ). Expression of the cellulose biosynthesis operon was found to be constitutive, however shown to fluctuate depending on growth phase and environmental conditions (Augimeri and Strap 2015 ; Hernández-Arriaga et al 2019 ; Ryngajłło et al 2019a ). Cellulose synthase enzyme activation occurs at the posttranslational level and is mediated by c-di-GMP ( bis -(3′,5′)-cyclic di-guanosine-mono-phosphate), which binds to the PilZ domain of the BcsA subunit and activates it allosterically (Ross et al 1985 ; Fujiwara et al 2013 ; Römling et al 2013 ).…”

“…The first global transcriptome of a Komagataeibacter sp. has been published and involves the study of effect of ethanol supplementation in the culture of K. xylinus E25 (Kubiak et al 2014 ; Ryngajłło et al 2019a ). This study has expanded the understanding of the positive effect of ethanol on BNC synthesis by revealing the gene expression changes triggering this effect, such as up-regulation of UDP-glucose synthesis pathway and down-regulation of glycolysis and acetan biosynthesis.…”