Effects of polyacrylamide‐co‐acrylic acid on cellulose production by Acetobacter xylinum

Abstract

Polyacrylamide-co-acrylic acid (PA) added to shake flask cultures of Acetobacter xylinum at concentrations up to 3 g dm −3 resulted in increased production of bacterial cellulose. For PA concentrations of 0-3 g dm −3 , 7-day cellulose production rose monotonically from 2.7 ± 0.8 to 6.5 ± 0.5 g dm −3 at a shaker speed of 175 rpm, and from 1.7 ± 0.01 to 3.7 ± 0.5 g dm −3 at shaker speed of 375 rpm. Addition of PA also changed the morphology of the biomass from amorphous/stringy forms to spheroidal particles with diameters ≤2 mm. Similarly, bioreactor cultures grown in the absence of PA formed long fibrous masses which deposited on the internals, while those grown in the presence of 1-2 g dm −3 PA formed small discrete particles with diameters ≤0.1 mm. Tests performed with 1 and 2 g dm −3 PA, and stirrer speeds from 500 to 900 rpm, appeared to give the highest cellulose concentration of 5.3 ± 0.7 g dm −3 in 64-68.5 h in the presence of 2 g dm −3 PA at 700 rpm, although this value was statistically indistinguishable from that obtained at 1 g dm −3 PA and 900 rpm. A qualitative model is proposed to describe the mechanisms by which PA affects biomass morphology, resulting in its advantageous formation as small, dispersed, spheroidal pellets. Quantitative analysis of the results gave inverse correlations between both the fraction of fructose carbon going to cellulose synthesis and the specific fructose consumption rate, and the maximum cellulose concentration and the fraction of fructose carbon going to by-product formation. Since cellulose yield was almost universally improved by higher polyacrylamide concentration, it appears likely that increased viscosity reduces fructose uptake rate by limiting mass transfer.

Effect of addition of sodium alginate on bacterial cellulose production by Acetobacter xylinum

“…Joseph et al [10] reported that 7-day BC production by A.xylinum BPR2001 rose from 2.7 to 6.5 g/l at a shake speed of 175 rpm and from 1.7 to 3.7 g/l at shake speed of 375 rpm at PCA concentrations of 0-0.3%. In the shake Xask experiments, a signiWcant increase in BC production was also attained by the addition of NaAlg, a water-soluble polysaccharide in our research.…”

“…Recently there are a few reports stating that addition of water-soluble polymers such as xanthan, agar, polyacrylamide-co-acylic acid (PCA), and acetan can increase relative viscosity of the broth to reduce shear stress, hinder coagulation of BC during the cultivation to form uniform smaller pellets, which are advantageous to transfer nutrients and oxygen into bacterial cells located inside and on the surface of the cellulose matrix, and further promote BC productivity into the medium, will assist in enhancing BC productivity [1,3,9,10]. On the other hand, various watersoluble polymers added into the medium are known to interfere with the aggregation of microWbrils into a normal ribbon assembly, aVect the crystallization of cellulose I and I and introduce the characteristic properties of these additives to attain BC composite materials [6].…”

Statistical optimization of culture conditions for bacterial cellulose production by Acetobacter xylinum BPR 2001 from maple syrup

“…High production of BC has been achieved using fructose as a carbon source (Joseph, Rowe, Margaritis, & Wan, 2003). More recently, unconventional feedstocks from renewable resources and waste streams have been investigated.…”

Improvements in the production of bacterial synthesized biocellulose nanofibres using different culture methods

“…Previous investigations showed that the higher shear caused by the impeller in the stirred tank bioreactor produces a negative effect on BC production, which decreases increasing stirring speed. 28,41 The CSL seems to have a negative impact on BC production in the airlift bioreactor as the CSL-fructose medium gave a productivity of 0.119 g L −1 h −1 . This is 75.7% less than the case when CSL was not used (i.e.…”

“…Joseph et al 41 studied the shake flask cultures with added polyacrylamide-co-acrylic acid using Acetobacter xylinum BPR2001 (ATCC No 700178). An increase in the production of BC was observed.…”