Gluconacetobacter xylinus is a primary strain producing bacterial cellulose (BC). In G. xylinus, BcsD is a subunit of cellulose synthase and is participated in the assembly process of BC. A series of G. xylinus with different expression levels of the bcsD gene were obtained by using the CRISPR/dCas9 technique. Analysis of the structural characteristics of BC showed that the crystallinity and porosity of BC changed with the expression of bcsD. The porosity varied from 59.95%-84.05%, and the crystallinity varied from 74.26%-93.75%, while the yield of BC did not decrease significantly upon changing the expression levels of bcsD. The results showed that the porosity of bacterial cellulose significantly increased, while the crystallinity was positively correlated with the expression of bcsD, when the expression level of bcsD was below 55.34%. By altering the expression level of the bcsD gene, obtaining BC with different structures but stable yield through a one-step fermentation of G. xylinus was achieved.
Cellulose/chemistry* ; Clustered Regularly Interspaced Short Palindromic Repeats ; Fermentation ; Gluconacetobacter xylinus/metabolism*

Microorganisms in nature have rich variety, whose sizes are from nano scale to micro scale. Therefore, microbes can be used as natural "building blocks" in nano/micro multi-level fabrication processes. At present, most of the bio-manufacturing methods do not apply to direct control of living microbes. Their microbiological global functions and superiorities are not available. In this paper, two novel nano/micro bio-fabrication approaches, micro-fluidic control method and magnetic control method have been established. The living microbes could be manipulated to form micro-scaled patterns or to move orientedly. By these approaches, living microbes are taken as nano/micro robots. We could employ their specific biological functions and regulate their controllable self-assembly, which is expected to design and create a series of new special functional materials and devices.
Bacteria ; metabolism ; Biomimetics ; methods ; Biotechnology ; Fungi ; metabolism ; Gluconacetobacter xylinus ; metabolism ; Industrial Microbiology ; Microfluidic Analytical Techniques ; methods ; Microtubules ; Nanotechnology ; Saccharomyces cerevisiae ; metabolism

Bacterial cellulose (BC) was prepared by Acetobacter xylinum in static culture. After purified by chemical treatment, the microstructure, chemical structure, crystal structure and mechanical property of BC were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD) and tensile strength measurement respectively, and compared with those of the imported bacterial cellulose wound dressing served as control sample (XBC). The results indicated that the diameter of the BC was (22 +/- 9) nm, and the crystallinity index was 89.71%. The tensile strength and the Young's mouduls of BC were significant higher than XBC both in wet and dry states. The biocompatibility of BC and XBC were evaluated by cytotoxicity test, delayed contact sensitization study in the Guinea Pig and skin irritation test. The results showed that BC had reliable biocompatibility as well as XBC. With the unique nanostructure, high crystallinity, high mechanical strength, and reliable biocompatibility, BC produced in our country as well as XBC can be used as a safe biomaterial for the medical applications.
Animals ; Biocompatible Materials ; chemistry ; Cellulose ; biosynthesis ; chemistry ; Culture Techniques ; Gluconacetobacter xylinus ; growth & development ; metabolism ; Guinea Pigs ; Materials Testing ; Nanoparticles ; Tensile Strength