Monitoring the Effect of pH on Bacterial Cellulose Production and Acetobacter xylinum 0416 Growth in a Rotary Discs Reactor (original) (raw)
Related papers
BioResources, 2014
In this study, microbial cellulose production by Acetobacter xylinum 0416 using standardized liquid pineapple waste was carried out in a 4-L rotary disc reactor (RDR). The objective of this study was to optimize the process parameters for production of microbial cellulose in the RDR. The effects of the disc rotation speed (5 to 12 rpm), pH (3.5 to 7.5), fermentation period (3 to 6 days), and inoculum concentration (3 to 20% v/v) on the microbial cellulose production were investigated. The optimum microbial cellulose yield was obtained using 10% (v/v) of inoculum concentration, whereby four days' duration gave the most productive yield. In addition, the highest production of microbial cellulose was obtained at a low disc rotation speed of 7 rpm and a pH of 5.0. Analysis of data performed a high coefficient of determination value (R 2 =0.875) represented by a mathematical model of optimized microbial cellulose production, Y =-200.437 + 7.180X 1 + 69.869X 2 + 4.369X 3 + 1.867X 4-0.512X 1 2-6.766X 2 2-0.585X 3 2-0.079X 4 2. From the results, it can be concluded that the foremost factors that affect the production of microbial cellulose in RDR were pH followed by inoculum concentration, disc rotation speed (rpm), and fermentation period.
Factors Influence on Bacterial Cellulose Growth in Static Reactors
Revista de Chimie
Synthesis of bacterial cellulose by Acetobacter xylinum in static conditions was performed. In order to optimize the cultivation conditions a factorial experiment with four factors (operating temperature, substrate concentration, co-substrate concentration and air specific flow rate) and two levels was used. Correlations between cellulose yield, respectively added water specific use, and process factors were established.
IOP Conference Series: Earth and Environmental Science, 2018
Bacterial cellulose was the result of fermentation by Acetobacterium xylinum. Fermentation medium that used in this research is is HS (Hestrin-Shramm) media with MgSO 4 as cofactor and also with 5% (v/v) glycerol and 0.8% (w/v) urea as additional carbon and nitrogen sources. This research focus is to determine the effect of acetic acid and ethanol as additives agent in the production of bacterial cellulose. Addition of additives to the fermentation medium aims to improve the characteristic of bacterial cellulose. Variable that used in this research is additive concentration (0.5%, 1%, 1.5%, and 2% v/v). Synthesized bacterial cellulose will be physically and mechanically characterize using dry thickness measurement, water capacity measurement, swelling ability, tensile strength and elongation at break measurement. Morphology measurement will be known through SEM (Scanning Electron Microscopy) and FTIR (Fourier Transform Infra Red) analysis. SEM analysis showed that addition of 1.5% (v/v) acetic acid to the fermentation medium gave more fiber on bacterial cellulose than addition of 1.5% ethanol, this result also supported by FTIR analysis. Rated of moisture content and swelling ratio of bacterial cellulose using 1.5% (v/v) ethanol higher when compared with 1.5% acetic acid on fermentation medium. Tensile strength and elongation at break analysis showed that bacterial cellulose has the highest tensile strength and the lowest elongation at break value with addition of 1.5% (v/v) acetic acid to the fermentation medium.
Cellulose production by Acetobacter xylinum BRC5 under agitated condition
Journal of Fermentation and Bioengineering, 1998
A potent cellulose producer, Acetobacter xyZinum BRCS, was cultivated in shaking flasks and jar fermeutors with glucose, fructose, sucrose and mixtures of these as carbon sources. It was confirmed that corn steep liquor (CSL) was cheap and a suitable organic nitrogen source for cellulose production by strain BRCS. When glucose was used as a sole carbon source, strain BRCS oxidized almost all the glucose to gluconic acid, thereafter it biosynthesized cellulose by utilizing the gluconic acid accumulated in the broth under limited glucose conditions. Since strain BRCS did not metabolize fructose to acid, the fermentation pattern of fructose was found to be typically growth associated with cellulose production. However, when glucose and fructose coexisted in the medium, strain BRCS preferentially metabolized all the glucose to gluconic acid. Thereafter, it produced cellulose mainly by utilizing fructose. Overall cellulose productivity in a jar fermentor ranged from 0.071 lo 0.086 g/l/h.
2000
Acetobacter xylinum TISTR 975 was cultured in a coconut water medium with added MgSO 4 and NH 4 HPO 4 . The optimum pH and amount of added sugar for the production of cellulose was found to be 4.75 and 5.1%w/v, respectively. The production of cellulose was measured on the eighth day of fermentation, while the depth of the liquid medium and surface area were varied. The depth of the medium for the highest cellulose production was 2.5 cm. The increment of medium volume by the depth of liquid medium was less effective for the production of cellulose than increasing the surface area. The highest amount of cellulose produced was 5.94 g/l from the fermentation conditions of 2.5 cm depth and liquid/air interface area of 359.12 cm 2 .
Utilization of acetate buffer to improve bacterial cellulose production by Gluconacetobacter xylinus
Food Hydrocolloids, 2016
The bacterial cellulose (BC) pellicle produced from Gluconacetobacter xylinus has many attractive properties to be used in food and biomedical applications. However, the by-product, gluconic acid produced during BC production will decrease the pH of culture that usually leads to a significant decrease of BC production by G. xylinus. To well control the pH of a static cultivation for BC pellicle production is not an easy task. In this study, acetate buffer was employed to maintain a pH suitable for BC production during static cultivation. The effect of buffer pH, ionic strength and surface area/volume (S/V) ratio of cultured medium on BC production was investigated. BC produced from 200 mM, pH 4.75 acetate buffered medium was 3.56 g/L, much higher than that obtained from YPD medium (0.66 g/L) and HS medium (1.23 g/L), respectively. When G. xylinus was cultivated at high glucose concentration (60 g/L) at S/V ratio of 0.55 cm-1 , the BC produced and conversion were improved to 7.23 g/L and 0.2, respectively. As S/V ratio increased to 1.31 cm-1 , a larger amount of gluconic acid (41.55 g/L) was obtained but with a slightly decreased BC production to 5.24 g/L. The results demonstrated that acetate buffered medium can effectively improve BC pellicle production in a static cultivation.
Bacterial Cellulose Production by Acetobacter xylinum Strains from Agricultural Waste Products
Biotechnology for Fuels and Chemicals, 2008
Bacterial cellulose is a biopolysaccharide produced from the bacteria, Acetobacter xylinum. Static batch fermentations for bacterial cellulose production were studied in coconut and pineapple juices under 30 °C in 5-l fermenters by using three Acetobacter strains: A. xylinum TISTR 998, A. xylinum TISTR 975, and A. xylinum TISTR 893. Experiments were carried out to compare bacterial cellulose yields along with growth kinetic analysis. Results showed that A. xylinum TISTR 998 produced a bacterial cellulose yield of 553.33 g/l, while A. xylinum TISTR 893 produced 453.33 g/l and A. xylinum TISTR 975 produced 243.33 g/l. In pineapple juice, the yields for A. xylinum TISTR 893, 975, and 998 were 576.66, 546.66, and 520 g/l, respectively. The strain TISTR 998 showed the highest productivity when using coconut juice. Morphological properties of cellulose pellicles, in terms of texture and color, were also measured, and the textures were not significantly different among treatments.
Of several organic nitrogen sources tested, corn steep liquor (CSL) was found to be the most suitable for cellulose production by Acetobacter xylinum subsp. sucrofermentans BPR 2001. When lactate, which was detected only in CSL, was added to culture media containing other nitrogen sources, cellulose production was stimulated to levels similar to that in CSL medium. Lactate was found to stimulate cell growth during the early stage of culture and shown to function by linking with the respiratory chain and generating energy for growth. Therefore, it was speculated that lactate acts as an accelerator driving the TCA cycle as well as an energy producer, resulting in high cellulose production and rapid cell growth.
Designing Economical Production of Microbial Cellulose from Waste Using Modified Bioreactor
Microbial cellulose produced by Acetobacter xylinum is an alternative source for plant cellulose in industrial use. Production of microbial cellulose is receiving great attention since they can be applied in many fields. This research is carried out to study the production of microbial cellulose using Rotary Discs Reactor (RDR) by Acetobacter xylinum bacteria in pineapple waste medium. RDR is a new method developed to enhance the production of microbial cellulose in industrial field because of few advantages: it allows the oxygen enrich air to be supplied continuously, homogenized culture in the medium by rotating discs and less hassle to scale up. This research involved few experimental works including fermentation process, comparison of the production yield from static culture and RDR using similar medium, and glucose analysis. The fermentation process was carried out at room temperature, pH 5.0, rotary speed at 7 rpm and 4 days of fermentation. The variable parameter in this rese...