Bacterial Nanocellulose Nitrates

Abstract

Bacterial nanocellulose (BNC) whose biosynthesis fully conforms to green chemistry principles arouses much interest of specialists in technical chemistry and materials science because of its specific properties, such as nanostructure, purity, thermal stability, reactivity, high crystallinity, etc. The functionalization of the BNC surface remains a priority research area of polymers. The present study was aimed at scaled production of an enlarged BNC sample and at synthesizing cellulose nitrate (CN) therefrom. Cyclic biosynthesis of BNC was run in a semisynthetic glucose medium of 10−72 L in volume by using the Medusomyces gisevii Sa-12 symbiont. The most representative BNC sample weighing 6800 g and having an α-cellulose content of 99% and a polymerization degree of 4000 was nitrated. The nitration of freeze-dried BNC was performed with sulfuric-nitric mixed acid. BNC was examined by scanning electron microscopy (SEM) and infrared spectroscopy (IR), and CN was explored to a fuller extent by SEM, IR, thermogravimetric analysis/differential scanning analysis (TGA/DTA) and 13C nuclear magnetic resonance (NMR) spectroscopy. The three-cycle biosynthesis of BNC with an increasing volume of the nutrient medium from 10 to 72 L was successfully scaled up in nonsterile conditions to afford 9432 g of BNC gel-films. CNs with a nitrogen content of 10.96% and a viscosity of 916 cP were synthesized. It was found by the SEM technique that the CN preserved the 3D reticulate structure of initial BNC fibers a marginal thickening of the nanofibers themselves. Different analytical techniques reliably proved the resultant nitration product to be CN. When dissolved in acetone, the CN was found to form a clear high-viscosity organogel whose further studies will broaden application fields of the modified BNC.

Scale-Up of Biosynthesis Process of Bacterial Nanocellulose

“…Compared to the previous findings on biosynthesis of BNC in a 72-L nutrient medium [38] for 7 days of cultivation, the yield declined by 1.4 times (from 5.20% to 3.45-3.69%) in case the sheet was taken out once, and the yield increased by 1.3 times from 5.20% to 6.98% in case two BNC sheets were removed from one volume of the nutrient medium (260 L). If the yields of the BNC sheets are compared within the given experiment, it can be noted that the overall yield of BNC in the second experiment is almost twice that in the first experiment: 6.98% (Sheet 2/1 + Sheet 2/2) versus 3.69% (Sheet 1).…”

“…where η is the BNC yield, %; m BNC is the BNC sample weight on an oven-dry basis (g); C g is the glucose concentration in the medium (g/L); V is the nutrient medium volume (L); and 0.9 is the conversion factor attributed to the water molecule detachment when glucose is polymerized into cellulose. The yield was calculated as reported [38].…”

Nanocellulose Based Filtration Membrane in Industrial Waste Water Treatment: A Review

“…CNF, CNC, and ECC are all derived from plants, while BNC is derived from microorganisms. BNC is a kind of nanofiber synthesized by aerobic bacteria [ 33 ]. Currently, the main strain synthesis of BNC is acetobacter xylinum.…”

Biosynthesis of Bacterial Cellulose by Extended Cultivation with Multiple Removal of BC Pellicles

“…FTIR can prove that the test substance is actually cellulose. For the microbial producer we used, that was demonstrated in our previous studies many times [ 19 , 32 , 39 , 50 ]. Besides, FTIR enables the measurements of the crystallinity index and the ratio of allomorph I α to I β in BC, more specifically these parameters allow the individual structure of BC to be identified, that is, how one type of BC differentiates from another BC type and what applications it may find.…”

“…The yield of BC was calculated by the equation: where η BC is the BC yield (%); m is the weight of the oven-dried matter (g); C G is the initial glucose concentration in the medium (g/L); V is the nutrient medium volume (L); and 0.90 is the coefficient attributed to the water molecule detachment from glucose monomeric units during BC biosynthesis. A similar calculation was used in the other studies [ 39 , 40 ]. The calculation admits that the BC moisture is 99.0%, which has been established many times by us through gravimetric analysis after freeze-drying.…”