Extracts of Agrobacterium tumefaciens incorporated UDP-[14 C]glucose into cellulose. When the extracts were fractionated into membrane and soluble components, neither fraction was able to synthesize cellulose. A combination of the membrane and soluble fractions restored the activity found in the original extracts. Extracts of cellulose-minus mutants showed no significant incorporation of UDP-glucose into cellulose. When mixtures of the extracts were made, the mutants were found to fall into two groups: extracts of mutants from the first group could be combined with extracts of the second group to obtain cellulose synthesis. No synthesis was observed when extracts of mutants from the same group were mixed. The groups of mutants corresponded to the two operons identified in sequencing the cel genes (A. G. Matthysse, S. White, and R. Lightfoot. J. Bacteriol. 177:1069-1075, 1995). Extracts of mutants were fractionated into membrane and soluble components, and the fractions were mixed and assayed for the ability to synthesize cellulose. When the membrane fraction from mutants in the celDE operon was combined with the soluble fraction from mutants in the celABC operon, incorporation of UDP-glucose into cellulose was observed. In order to determine whether lipid-linked intermediates were involved in cellulose synthesis, permeabilized cells were examined for the incorporation of UDP-[ 14 C]glucose into material extractable with organic solvents. No radioactivity was found in the chloroform-methanol extract of mutants in the celDE operon, but radioactive material was recovered in the chloroform-methanol extract of mutants in the celABC operon. The saccharide component of these compounds was released after mild acid hydrolysis and was found to be mainly glucose for the celA insertion mutant and a mixture of cellobiose, cellotriose, and cellotetrose for the celB and celC insertion mutants. The radioactive compound extracted with chloroform-methanol from the celC insertion mutant was incorporated into cellulose by membrane preparations from celE mutants, which suggests that this compound is a lipid-linked intermediate in cellulose synthesis.Cellulose, which is made by plants and by some bacteria and fungi, is one of the most abundant biologically produced materials. It is a relatively simple molecule consisting of a linear chain of ␤-1,4-glucose residues without any modifications or side chains. Despite these facts, the mechanism of cellulose synthesis is not understood in detail (5, 7, 19). We do not know whether all organisms which make cellulose use similar pathways or whether there exist alternate pathways used by different groups of organisms.The mechanism of cellulose synthesis has been examined most extensively in Acetobacter xylinum. The precursor is UDPglucose. Cell extracts of the bacteria incorporate UDP-glucose into cellulose (1, 11). An unusual cofactor, cyclic diguanylic acid, is required for cellulose synthesis in this organism. The cofactor can be degraded by a protein contained in the cell extracts, and it ...

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Bacterial nanocellulose (BNC) has been emerging as a biomaterial of considerable significance in a number of industrial sectors because of its remarkable physico-chemical and biological characteristics. High capital expenses, manufacturing costs, and a paucity of some well-scalable methods, all of which lead to low BNC output in commercial scale, are major barriers that must be addressed. Advances in production methods, including bioreactor technologies, static intermittent, and semi-continuous fed batch technologies, and innovative outlay substrates, may be able to overcome the challenges to BNC production at the industrial scale. The novelty of this review is that it highlights genetic modification possibilities in BNC production to overcome existing impediments and open up viable routes for large-scale production, suitable for real-world applications. This review focuses on various production routes of BNC, its properties, and applications, especially the major advancement in food, personal care, biomedical and electronic industries.

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