Sains Malaysiana 45(3)(2016): 393–400

An Evaluation of Fermentation Period and Discs Rotation Speed of Rotary Discs Reactor for Bacterial Cellulose Production

(Penilaian Tempoh Penapaian dan Kelajuan Putaran Cakera melalui Reaktor Cakera Berputar untuk Pengeluaran Selulosa Bakteria)

KHAIRUL AZLY ZAHAN^1,3, NORHAYATI PA’E¹ & IDA IDAYU MUHAMAD^1,2*

¹Bioprocess Engineering Department, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor Darul Takzim, Malaysia

²Cardio Engineering Centre IJN-UTM, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor Darul Takzim, Malaysia

³Section of Bioengineering Technology, Malaysian Institute of Chemical and Bioengineering Technology, Universiti Kuala Lumpur, 78000 Alor Gajah, Melaka Bandar Bersejarah, Malaysia

Received: 6 January 2015/Accepted: 1 September 2015

ABSTRACT

Acetobacter xylinum strains are known as efficient producers of cellulose. A. xylinum is an obligate aerobic bacterium that has an oxygen-based metabolism. The dissolved oxygen (DO) concentration in a rotary discs reactor (RDR) is one of the most important factors that need to be observed during the cellulose synthesis by these bacteria. In this study, the effects of different discs rotation speed (5, 7, 9 and 12 rpm) and fermentation period (3, 4, 5 and 6 days) on the DO concentration and production of bacterial cellulose in a 10-L RDR were examined. The highest yield was obtained at 7 rpm with a total dried weight of 28.3 g for 4 days fermentation. The results showed that the DO concentration in the 10-L RDR increased in the range of 13 to 17% with increasing of discs rotation speed from 7 to 12 rpm. However, fermentation with high discs rotation speed at 12 rpm reduced the bacterial cellulose production. Analysis of data using Statistica 8.0 showed a high coefficient of determination value (R₂ = 0.92). In conclusion, discs rotation speed gave more significant effect on the DO concentration and production of bacterial cellulose in 10-L RDR compared to fermentation period. This was further combined with synergistic effect from sufficient consumption of oxygen for the enhanced production of bacterial cellulose and providing the controlled environment for encouraging bacterial growth throughout the fermentation process.

Keywords: Acetobacter xylinum; bacterial cellulose; discs rotation speed; dissolved oxygen; fermentation period; rotary discs reactor (RDR)

ABSTRAK

Strain Acetobacter xylinum dikenali sebagai pengeluar selulosa yang cekap. A. xylinum adalah bakteria aerobik yang mempunyai metabolisme berasaskan oksigen. Kepekatan oksigen terlarut (DO) di dalam reaktor cakera berputar (RDR) adalah salah satu faktor terpenting yang perlu diperhatikan semasa pengeluaran selulosa oleh bakteria ini. Dalam kajian ini, kesan daripada kelajuan putaran cakera yang berbeza (5, 7, 9 dan 12 rpm) dan tempoh penapaian (3, 4, 5 dan 6 hari) terhadap kepekatan oksigen terlarut (DO) dan jumlah pengeluaran selulosa di dalam 10-L RDR telah dikaji. Hasil tertinggi telah diperoleh pada kelajuan putaran cakera 7 rpm dengan jumlah berat kering sebanyak 28.3 g selama 4 hari penapaian. Keputusan juga menunjukkan bahawa kepekatan oksigen terlarut (DO) di dalam 10-L RDR meningkat dalam julat 13 hingga 17% dengan peningkatan kelajuan putaran antara 7 hingga 12 rpm. Walau bagaimanapun, penapaian dengan kelajuan cakera yang tinggi iaitu pada 12 rpm menyebabkan pengeluaran selulosa berkurangan. Analisis data menggunakan Statistica 8.0 menunjukkan pekali nilai penentuan (R₂ = 0.92) yang tinggi. Kesimpulannya, kelajuan putaran cakera memberikan kesan yang lebih besar terhadap kepekatan oksigen terlarut dan penghasilan selulosa di dalam 10-L RDR berbanding tempoh penapaian. Ini seterusnya digabungkan dengan kesan sinergistik daripada penggunaan oksigen yang mencukupi bagi meningkatkan pengeluaran selulosa dan menyediakan persekitaran terkawal untuk menggalakkan pertumbuhan bakteria sepanjang proses penapaian.

Kata kunci: Acetobacter xylinum; kelajuan putaran cakera; oksigen terlarut; reaktor cakera berputar (RDR); selulosa bakteria; tempoh penapaian

REFERENCES

Brown, A.J. 1886. On an acetic ferment which form cellulose. Journal of the Chemical Society, Faraday Transactions 49: 432-439.

Chao, Y., Sugano, Y. & Shoda, M. 2001. Bacterial cellulose production under oxygen enriched air at different fructose concentrations in 50 liters internal loop airlift bioreactor. Applied and Microbial Biotechnology 55(6): 673-679.

Chawla, P.R., Bajaj, I.B., Survase, S.A. & Singhal, R.S. 2008. Microbial cellulose: Fermentative production and applications. Food Technology Biotechnology 47(2): 107-124.

Fontana, J.D., deSouza, A.M., Fontana, C.K., Torriani, I.L., Moreschi, J.C., Gallotti, B.J., deSouza, S.J., Narcisco, G.P., Bichara, J.A. & Farah, L.F.X. 1990. Acetobacter cellulose pellicle as a temporary skin substitute. Applied Biochemistry and Biotechnology 24(25): 253-263.

Hestrin, S. & Schramm, M. 1954. Factors effecting production of cellulose at the air/liquid interface of a culture of Acetobacter xylinum. Journal of General Microbiology 11(1): 123-129.

Hwang, J.W., Yang, Y.K., Hwang, J.K., Pyun, R.Y. & Kim, Y.S. 1999. Effects of pH and dissolved oxygen on cellulose production by Acetobacter xylinum BRC5 in agitated culture. Journal of Bioscience and Bioengineering 88(2): 183-188.

Joglekar, A.M. & May, A.T. 1987. Product excellence through design of experiments. Cereal Food World 32: 857-868.

Jung, J.Y., Khan, T., Park, J.K. & Chang, H.N. 2007. Production of bacterial cellulose by Gluconacetobacter hansenii using a novel bioreactor equipped with a spin filter. Korean Journal of Chemical Engineering 24(2): 265-271.

Jung, W.H., Young, K.Y., Jae, K.H., Yu, R.P. & Yu, S.K. 1999. Effects of pH and dissolved oxygen on cellulose production

by Acetobacter xylinum BRCS in agitated culture. Journal of Bioscience and Bioengineering 88(2): 183-188.

Kim, S.Y., Kim, J.N., Wee, Y.J., Park, D.H. & Ryu, H.W. 2007. Bacterial cellulose production by Gluconacetobacter sp. RKY5 in a rotary biofilm contactor. Applied Biochemistry and Biotechnology 137(1-12): 529-537.

Kouda, T., Yano, H. & Yoshinaga, F. 1997. Effect of agitator configuration on bacterial cellulose productivity in aerated and agitated culture. Journal of Fermentation and Bioengineering 83(4): 371-376.

Krystynowicz, A., Koziołkiewicz, A., Wiktorowska, J.A., Bielecki, S., Klemenska, E., Masny, A. & Płucienniczak, A. 2005. Molecular basis of cellulose biosynthesis disappearance in submerged culture of Acetobacter xylinum. Acta Biochimia Polonica 52(3): 691-698.

Krystynowicz, A., Czaja, W., Wiktorowska-Jezierska, A., Goncalves-Miskiewicz, M., Turkiewicz, M. & Bielecki, S. 2002. Factors affecting the yield and properties of bacterial cellulose. Journal of Industrial Biotechnology 29(4): 189- 195.

Ougiya, I.I., Watanabe, K., Morinaga, Y. & Yoshinaga, F. 1997. Emulsion effect of bacterial cellulose. Biosci. Biotech. Biochem 61: 1541-1545.

Pa’e, N., Zahan, K.A. & Muhamad, I.I. 2011. Production of biopolymer from Acetobacter xylinum using different fermentation methods. International Journal of Engineering & Technology IJET-IJENS 11(5): 90-98.

Quoc, L.P.T., Xinh, N.T.K., Nguyet, H.T.K. & Xuyen, N.T.H. 2012. Application of response surface methodology (RSM) in condition optimization for essential oil production from Citrus latifolia. Emir. J. Food Agric. 24(1): 25-30.

Ruka, D.R., Simon, G.P. & Dean, K.M. 2012. Altering the growth conditions of Gluconacetobacter xylinus to maximize the yield of bacterial cellulose. Carbohydrate Polymers 89(2): 613-622.

Shoda, M. & Sugano, Y. 2005. Recent advances in bacterial cellulose production. Biotechnol. Bioprocess. Eng. 10: 1-8.

Suwannapinunt, N., Burakorn, J. & Thaenthanee, S. 2007. Effect of culture conditions on bacterial cellulose (BC) production from Acetobacter xylinum TISTR976 and physical properties of BC parchment paper. Journal of Science Technology 14(4): 357-365.

Zahan, K.A., Pa’e, N. & Muhamad, I.I. 2015. Monitoring the effect of pH on bacterial cellulose production and Acetobacter xylinum 0416 growth in a rotary discs reactor. The Arabian Journal for Science and Engineering 40(7): 1881-1885.

Zahan, K.A., Pa’e, N. & Muhamad, I.I. 2014. Process parameters for fermentation in a rotary disc reactor for optimum microbial cellulose production using response surface methodology. BioResources 9(2): 1858-1872.

Zahan, K.A. 2014. Process parameters for microbial cellulose production by Acetobacter xylinum in rotary disc reactor. Master Degree Thesis, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Skudai, Johor (Unpublished).

Zeng, X., Small, D.P. & Wan, W. 2011. Statistical optimization of culture conditions for bacterial cellulose production by Acetobacter xylinum BPR 2001 from maple syrup. Carbohydrate Polymers 85(3): 506-513.

*Corresponding author; email: idayu@cheme.utm.my