- Email: [email protected]
Identification and partial characterization of pediocin PA-1 producing Pediococcus pentosaceus associated in traditional Thai fermented beef (mum)
S748
Abstracts / Journal of Biotechnology 136S (2008) S743–S750
taste, sour taste, bitter taste, and overall acceptability were determined by 5-point just-about-right (JAR) scale. Subsequently, those samples were analyzed for ethanol, pH, brix, sugar, tannin, organic acids, aroma and color. The chemical characteristics of six red wines were significantly different in ethanol, pH, brix, sugar content, tannin, organic acids, and color. Among them, a wine gained the highest overall acceptability score and its chemical analysis results were 9.4 brix, 3.7% of sugar content, pH 3.5, 10% of ethanol, 0.14% of tannin, 5.74 mg/ml of total acids and color L(12.04 ± 0.01), a (33.90 ± 0.19), and b (8.22). The test results revealed that Korean consumers generally prefer sweet taste to dry, flat taste to bitter, and fruity aroma to others. The detailed analysis results will be presented.
Acknowledgements We thank Silvestre Lopez for their help in samples preparation. This work was supported by the project SIP: 20082322. References Escalante, A., Rodriguez, M., Martinez, A., López-Munguía, A., Bolivar, F., Gosset, G., 2004. Characterization of bacterial diversity in Pulque a traditional Mexican alcoholic fermented beverage, as determined by 16S rDNA analysis. FEMS Microbiol. Lett. 235, 273–279. Sánchez-Marroquín, A., 1967. Estudios sobre la microbiología del pulque XX. Proceso industrial para la elaboración técnica de la bebida. Rev. Lat. Microbiol. Parasite 9, 87–90.
doi:10.1016/j.jbiotec.2008.07.1780 References Koh, K.H., Lee, S.J., Lee, J.E., Kim, H.W., Kim, S.S., 2006. Development of Korean red wines using Vitis labrusca varieties: instrumental and sensory characterization. Food Chem. 94, 385–393. Recamales, A.F., Sayago, A., Gonzalez-Miret, M.L., Hernanz, D., 2006. The effect of time and storage conditions on the phenolic composition and colour of white wine. Food Res. Int. 39, 220–229. Yebra, M.C., Gallego, M., Valcárcel, M., 1995. Indirect flow injection determination of tannins in wines and tea by atomic absorption spectrometry. Anal. Chim. acta 308, 357–363.
VIII2-P-012 Identification and partial characterization of pediocin PA-1 producing Pediococcus pentosaceus associated in traditional Thai fermented beef (mum) Adisorn Swetwiwathana 1,∗ , Yaowalak Surapantapisit 1 , Takeshi Zendo 2 , Jiro Nakayama 2 , Kenji Sonomoto 2 1
doi:10.1016/j.jbiotec.2008.07.1779 VIII2-P-011 Microbiological characterization and quantification of ethanol in pulque, a tradicional Mexican alcoholic fermented beverage Mario Cervantes-Contreras 1,∗ , Aura Marina Pedroza-Rodríguez 2 1
Departamento de Matemáticas, Unidad Profesional Interdisciplinaria de Biotecnología-Instituto Politécnico Nacional, Ticoman, México, D.F. 07340, Mexico 2 Grupo de Biotecnología Ambiental e Industrial. Laboratorio de Biotecnología Aplicada. Departamento de Microbiología. Pontificia Universidad Javeriana, Carrera 7 No. 43-82 Bogotá, Colombia
Pulque is a tradicional Mexican alcoholic fermented beverage produced from the sap known as aguamiel, which is extracted from several species of maguey (Agave americana, A. Ferox, A. Mapisaga, A. Salmiana) (Sánchez-Marroquín, 1967; Escalante et al., 2004). Pulque production consist of three types of fermentations: acidic, alcoholic, and viscous, making this traditional beverage an interesting environment were microorganisms or genes with potential biotechnological applications, such as those encoding sugar transporters, hydrolytic enzymes, EPS, lactic acid or ethanol production, could be isolated. Home made pulque samples (P1: aguamiel, P2: seed, P3: 24 h of fermentation and P4: 48 h of fermentation) were collected from town San Simon Tlatlahuquitepec in Tlaxcala, Mexico. Three strains were isolated from pulque. Different morphological groups were identified: Gram-negative coccobacilli, regular nonsporing Gram-positive rods and yeast. Each strain was identified with Zymomonas sp., Lactobacillus sp. and Saccharomyces sp. (Escalante et al., 2004). The developed consortium was responsible for the alcoholic, acid, and viscous fermentation which are special characteristics of this traditional Mexican beverage. The alcohol content varies in function of the fermentation time. They were determined by gas chromatography and Raman spectroscopy. The end product (sample P4) has a high content of proteins (1 g/l), sugar reducers (4.75 g/l) and microbial populations in ranks of 45 × 108 UFC/mL for Saccharomyces sp., 41 × 107 UFC/mL for Zymomonas sp. and 34 × 106 UFC/mL for Lactobacillus sp.
Department of Agro-industry, Faculty of Agro-Industry, King Mongkut’s Institute of Technology Ladkrabang (KMITL), Bangkok 10520, Thailand 2 Laboratory of Microbial Technology, Department of Bioscience and Biotechnology, Faculty of Agricultural Graduate School, Kyushu University. 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan E-mail address: [email protected] (A. Swetwiwathana).
Lactic acid bacteria (LAB) strain M13, which was isolated from Mum and reported as a bacteriocin-producing strain (Piayura et al., 2006) was further studied for strain identification using 16S rDNA sequences (Anderson and McKay, 1983; Swetwiwathana, 2005) and commercial carbohydrate fermentation kit (API 50 CH -bioMorieux Vitek, Inc., Hazelwood, MO.). In addition, identification of bacteriocins produced by this strain using amino acid sequences and PCR amplification of DNA encoding bacteriocin-producing genes of this strain using specific primers followed by DNA sequences was also studied (Swetwiwathana, 2005; Ennahar et al., 1996). The results from microscopic test implied that the microorganism belonged to gram positive tetrad cocci and was 100% identical to Pediococcus pentosaceus by the rapid API carbohydrate fermentation patterns. The results also revealed the 100% of identity related to P. pentosaceus by the complete DNA sequence analysis. Molecular weight of the purified bacteriocins was about 4,627 Da, which was identical to that of pediocin AcH or PA-1 produced by different P. acidilactici strains. Confirmation by sequencing the amplified polymerase chain reaction (PCR) of gene encoding this bacteriocins with pediocin PA-1 gene –specific primers also exhibited 100% identical sequences to pediocin PA-1. This is the first report of pediocin PA-1 producer strain of P. pentosaceus M13 isolated from Mum. This LAB is currently under further investigation to implement its application in improving the fermentation quality and safety of this traditional Thai fermented beef. Keywords: pediocin PA-1; Pediococcus pentosaceus; Thai fermented beef; Mum References Anderson, D.G., McKay, L.L., 1983. Simple and rapid method for isolating large plasmid DNA from lactic streptococci. Appl. Environ. Microbiol. 46, 549–562. Ennahar, S., Aoude-Werner, D., Sorokine, O., Van Dorsselaer, A., Bringel, F., Hubert, J.-C., Hasselmann, C., 1996. Production of pediocin AcH by Lactobacillus plan-
Abstracts / Journal of Biotechnology 136S (2008) S743–S750 tarum WHE 92 isolated from cheese. Appl. Environ. Microbiol. 62 (12), 4381–4387. Piayura, S., Pinsirodom, P., Surapantapisit, Y., Swetwiwathana., A., 2006. In: Declan Troy, Rachel Pearce, Briege, Byrne, Joseph Kerry (Eds.), The 52nd ICoMST: Harnessing and Exploiting Global Opportunities. Wageningen Academic Publishers, The Netherlands, pp. 329–330. Swetwiwathana, A., 2005. Microbiological Quality Enhancement of Thai Fermented Meat Product (Nham) Using Nham Associated Pediocin-producing Lactic Acid Bacteria (Pediococcus pentosaceus TISTR 536), Ph.D. Thesis of Department of Bioscience and Biotechnology, Kyushu University, Japan.
S749
Vaidya, D., Vaidya, M., 2000. Fruit Juices and Juice beverages. In: Verma, L.R., Joshi, V.K. (Eds.), Post Harvest Technology of Fruits and Vegetables. Indus Publishing Company, New Delhi, pp. 708–709.
doi:10.1016/j.jbiotec.2008.07.1782 VIII2-P-015
doi:10.1016/j.jbiotec.2008.07.1781
Effect of fermentation conditions on the production and characteristics of cellulose pellicles from Acetobacter xylinum
VIII2-P-013
Sumate Tantratian ∗ , Boonyarit Pradistsuwana
Preparation and evaluation of appetizer’s from lactic acid fermented vegetables
Department of Food Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
V.K. Joshi 1 , Somesh Sharma 1,∗ , Neerja Rana 2
E-mail address: [email protected] (S. Tantratian).
1
Department of Postharvest Technology, Dr. Y S Parmer University of Horticulture and Forestry, Nauni, Solan 173230, Himachal Pradesh, India 2 Department of Vegetable, Dr. Y S Parmer University of Horticulture and Forestry, Nauni, Solan 173230, Himachal Pradesh, India E-mail addresses: [email protected] [email protected] (S. Sharma).
(V.K.
Joshi),
The tremendous increase in consumers demand for fresh like products containing natural ingredients, changing food patterns and convenience has led to the development of minimally processed products using lactic acid bacterial (LAB) cultures. In the present studies, an attempt was made to develop and evaluate the appetizers from fermented vegetables. The vegetables were fermented using sequential culture of lactic acid bacteria viz., Lactobacillus plantarum (NCDC 020), Pediococcus cerevisiae (NCDC 038) and Streptococcus lactis var diacetylactis (NCDC 061) as per the conditions optimized earlier (Joshi et al., 2008; Sharma and Joshi, 2007). Different combinations of fermented vegetables viz., carrot, radish and cucumber with pear and mango pulps were made separately and were processed as per the routine practice (Vaidya and Vaidya, 2000). All the appetizers were prepared having a constant TSS of 45◦ B and different combinations of fermented pulp viz., 10, 20 and 30 with fruit pulps of mango, apricot and pear as per the respective combinations. A common recipe of appetizer was followed in their preparation. The titratable acidity of carrot, radish and cucumber based appetizers ranged from 1.12% to 1.72% in different appetizers. The blending ratio influenced the titratable acidity, brix-acid ratio, pH and colour of appetizer so prepared. Physico-chemical and sensory characteristics of all the appetizers prepared met the prescribed, specifications. Among various carrot and cucumber based appetizers, product prepared with fermented carrot only and the appetizer with blend of 10% fermented cucumber + 20% apricot were preferred to others. In the sensory quality evaluation, the fermented radish based appetizer having 20% radish + 10% apricot was rated the best. Out of the three vegetables and pulps, radish based appetizer having 20% radish + 10% apricot had the highest overall acceptability and was rated the best. The cost of production of fermented vegetable based appetizers was also economical. References Joshi, V.K., Sharma, Somesh, Thakur, N.S., 2008. Effect of temperature, salt, concentration and type of microorganism on lactic acid fermentation of carrot. Acta Alimentaria. 37 (2), 205–219. Sharma, Somesh, Joshi, V.K., 2007. Influence of temperature and salt concentration on lactic acid fermentation of radish (Raphnus sativus). J. Food Sci. Technol. 44 (6), 611–614.
Ruthaikongtaworn, Chidphong
Acetobacter xylinum was cultured in coconut medium (Punsri et al., 2003) and incubated in different conditions, static culture, shake culture and in a drum reactor. The oxygen transfer rate was determined by gassing out method (Stanbury et al., 1995). In the static culture, the coconut medium had the oxygen transfer rate of 2.65 × 10−4 mg oxygen/l min, while the shaking at 100 rpm and in a drum reactor which vertically rotating at 5 rpm in a rotating reactor had 0.2526 and 0.116 mg oxygen/l min, respectively. During fermentation, the dissolved oxygen in static culture was dropped sharply to unable to measure within the first day, while in rotating drum reactor the dissolved oxygen was gradually decreased and remained at about 0.1 mg/l after the fourth day of fermentation. The excessive dissolved oxygen in the liquid medium was found only in the shaking culture. The rotating drum reactor provided the heaviest pellicle wet weight and highest cellulose content at 36.20 g/100 ml and 0.57 g/100 ml media after 7 day incubation. The static culture and shake culture produced the same wet pellicle weight at about 28 g/100 ml but contained different in the amount of cellulose. From the results showed that the culture needed necessary amount of oxygen to produce cellulose. The excess amount of oxygen could take away the glucose for other metabolisms (Hwang et al., 1999) instead of cellulose production. The scanning electron micrographs (SEM) showed that the pellicles from static culture had the tightest fibril fabrication with biggest cells size. The shake culture pellicle had the smallest fibril with largest distance between fibrils. It also had capability to hold water less than pellicles from static and rotating drum reactor. References Hwang, J.W., Yang, Y.K., Hwang, J.K., Pyun, Y.R., Kim, Y.S., 1999. Effects of dissolved oxygen on cellulose production by Acetobacter xylinum BRC5 in agitated culture. J. Biosci. Bioeng. 88 (2), 183–188. Punsri, A., Tammarate, P., Krusong, W., Tantratian, S., 2003. The liquid/air interface area and depth of liquid medium suitable for cellulose production from Acetobacter sp. TISTR 975. J. Sci. Res. Chulalongkorn Univ. 28 (1), 35–43. Stanbury, P.F., Whitaker, A., Hall, S.J., 1995. Principle of Fermentation Technology. Pergamon Press, Oxford.
doi:10.1016/j.jbiotec.2008.07.1783
Abstracts / Journal of Biotechnology 136S (2008) S743–S750
taste, sour taste, bitter taste, and overall acceptability were determined by 5-point just-about-right (JAR) scale. Subsequently, those samples were analyzed for ethanol, pH, brix, sugar, tannin, organic acids, aroma and color. The chemical characteristics of six red wines were significantly different in ethanol, pH, brix, sugar content, tannin, organic acids, and color. Among them, a wine gained the highest overall acceptability score and its chemical analysis results were 9.4 brix, 3.7% of sugar content, pH 3.5, 10% of ethanol, 0.14% of tannin, 5.74 mg/ml of total acids and color L(12.04 ± 0.01), a (33.90 ± 0.19), and b (8.22). The test results revealed that Korean consumers generally prefer sweet taste to dry, flat taste to bitter, and fruity aroma to others. The detailed analysis results will be presented.
Acknowledgements We thank Silvestre Lopez for their help in samples preparation. This work was supported by the project SIP: 20082322. References Escalante, A., Rodriguez, M., Martinez, A., López-Munguía, A., Bolivar, F., Gosset, G., 2004. Characterization of bacterial diversity in Pulque a traditional Mexican alcoholic fermented beverage, as determined by 16S rDNA analysis. FEMS Microbiol. Lett. 235, 273–279. Sánchez-Marroquín, A., 1967. Estudios sobre la microbiología del pulque XX. Proceso industrial para la elaboración técnica de la bebida. Rev. Lat. Microbiol. Parasite 9, 87–90.
doi:10.1016/j.jbiotec.2008.07.1780 References Koh, K.H., Lee, S.J., Lee, J.E., Kim, H.W., Kim, S.S., 2006. Development of Korean red wines using Vitis labrusca varieties: instrumental and sensory characterization. Food Chem. 94, 385–393. Recamales, A.F., Sayago, A., Gonzalez-Miret, M.L., Hernanz, D., 2006. The effect of time and storage conditions on the phenolic composition and colour of white wine. Food Res. Int. 39, 220–229. Yebra, M.C., Gallego, M., Valcárcel, M., 1995. Indirect flow injection determination of tannins in wines and tea by atomic absorption spectrometry. Anal. Chim. acta 308, 357–363.
VIII2-P-012 Identification and partial characterization of pediocin PA-1 producing Pediococcus pentosaceus associated in traditional Thai fermented beef (mum) Adisorn Swetwiwathana 1,∗ , Yaowalak Surapantapisit 1 , Takeshi Zendo 2 , Jiro Nakayama 2 , Kenji Sonomoto 2 1
doi:10.1016/j.jbiotec.2008.07.1779 VIII2-P-011 Microbiological characterization and quantification of ethanol in pulque, a tradicional Mexican alcoholic fermented beverage Mario Cervantes-Contreras 1,∗ , Aura Marina Pedroza-Rodríguez 2 1
Departamento de Matemáticas, Unidad Profesional Interdisciplinaria de Biotecnología-Instituto Politécnico Nacional, Ticoman, México, D.F. 07340, Mexico 2 Grupo de Biotecnología Ambiental e Industrial. Laboratorio de Biotecnología Aplicada. Departamento de Microbiología. Pontificia Universidad Javeriana, Carrera 7 No. 43-82 Bogotá, Colombia
Pulque is a tradicional Mexican alcoholic fermented beverage produced from the sap known as aguamiel, which is extracted from several species of maguey (Agave americana, A. Ferox, A. Mapisaga, A. Salmiana) (Sánchez-Marroquín, 1967; Escalante et al., 2004). Pulque production consist of three types of fermentations: acidic, alcoholic, and viscous, making this traditional beverage an interesting environment were microorganisms or genes with potential biotechnological applications, such as those encoding sugar transporters, hydrolytic enzymes, EPS, lactic acid or ethanol production, could be isolated. Home made pulque samples (P1: aguamiel, P2: seed, P3: 24 h of fermentation and P4: 48 h of fermentation) were collected from town San Simon Tlatlahuquitepec in Tlaxcala, Mexico. Three strains were isolated from pulque. Different morphological groups were identified: Gram-negative coccobacilli, regular nonsporing Gram-positive rods and yeast. Each strain was identified with Zymomonas sp., Lactobacillus sp. and Saccharomyces sp. (Escalante et al., 2004). The developed consortium was responsible for the alcoholic, acid, and viscous fermentation which are special characteristics of this traditional Mexican beverage. The alcohol content varies in function of the fermentation time. They were determined by gas chromatography and Raman spectroscopy. The end product (sample P4) has a high content of proteins (1 g/l), sugar reducers (4.75 g/l) and microbial populations in ranks of 45 × 108 UFC/mL for Saccharomyces sp., 41 × 107 UFC/mL for Zymomonas sp. and 34 × 106 UFC/mL for Lactobacillus sp.
Department of Agro-industry, Faculty of Agro-Industry, King Mongkut’s Institute of Technology Ladkrabang (KMITL), Bangkok 10520, Thailand 2 Laboratory of Microbial Technology, Department of Bioscience and Biotechnology, Faculty of Agricultural Graduate School, Kyushu University. 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan E-mail address: [email protected] (A. Swetwiwathana).
Lactic acid bacteria (LAB) strain M13, which was isolated from Mum and reported as a bacteriocin-producing strain (Piayura et al., 2006) was further studied for strain identification using 16S rDNA sequences (Anderson and McKay, 1983; Swetwiwathana, 2005) and commercial carbohydrate fermentation kit (API 50 CH -bioMorieux Vitek, Inc., Hazelwood, MO.). In addition, identification of bacteriocins produced by this strain using amino acid sequences and PCR amplification of DNA encoding bacteriocin-producing genes of this strain using specific primers followed by DNA sequences was also studied (Swetwiwathana, 2005; Ennahar et al., 1996). The results from microscopic test implied that the microorganism belonged to gram positive tetrad cocci and was 100% identical to Pediococcus pentosaceus by the rapid API carbohydrate fermentation patterns. The results also revealed the 100% of identity related to P. pentosaceus by the complete DNA sequence analysis. Molecular weight of the purified bacteriocins was about 4,627 Da, which was identical to that of pediocin AcH or PA-1 produced by different P. acidilactici strains. Confirmation by sequencing the amplified polymerase chain reaction (PCR) of gene encoding this bacteriocins with pediocin PA-1 gene –specific primers also exhibited 100% identical sequences to pediocin PA-1. This is the first report of pediocin PA-1 producer strain of P. pentosaceus M13 isolated from Mum. This LAB is currently under further investigation to implement its application in improving the fermentation quality and safety of this traditional Thai fermented beef. Keywords: pediocin PA-1; Pediococcus pentosaceus; Thai fermented beef; Mum References Anderson, D.G., McKay, L.L., 1983. Simple and rapid method for isolating large plasmid DNA from lactic streptococci. Appl. Environ. Microbiol. 46, 549–562. Ennahar, S., Aoude-Werner, D., Sorokine, O., Van Dorsselaer, A., Bringel, F., Hubert, J.-C., Hasselmann, C., 1996. Production of pediocin AcH by Lactobacillus plan-
Abstracts / Journal of Biotechnology 136S (2008) S743–S750 tarum WHE 92 isolated from cheese. Appl. Environ. Microbiol. 62 (12), 4381–4387. Piayura, S., Pinsirodom, P., Surapantapisit, Y., Swetwiwathana., A., 2006. In: Declan Troy, Rachel Pearce, Briege, Byrne, Joseph Kerry (Eds.), The 52nd ICoMST: Harnessing and Exploiting Global Opportunities. Wageningen Academic Publishers, The Netherlands, pp. 329–330. Swetwiwathana, A., 2005. Microbiological Quality Enhancement of Thai Fermented Meat Product (Nham) Using Nham Associated Pediocin-producing Lactic Acid Bacteria (Pediococcus pentosaceus TISTR 536), Ph.D. Thesis of Department of Bioscience and Biotechnology, Kyushu University, Japan.
S749
Vaidya, D., Vaidya, M., 2000. Fruit Juices and Juice beverages. In: Verma, L.R., Joshi, V.K. (Eds.), Post Harvest Technology of Fruits and Vegetables. Indus Publishing Company, New Delhi, pp. 708–709.
doi:10.1016/j.jbiotec.2008.07.1782 VIII2-P-015
doi:10.1016/j.jbiotec.2008.07.1781
Effect of fermentation conditions on the production and characteristics of cellulose pellicles from Acetobacter xylinum
VIII2-P-013
Sumate Tantratian ∗ , Boonyarit Pradistsuwana
Preparation and evaluation of appetizer’s from lactic acid fermented vegetables
Department of Food Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
V.K. Joshi 1 , Somesh Sharma 1,∗ , Neerja Rana 2
E-mail address: [email protected] (S. Tantratian).
1
Department of Postharvest Technology, Dr. Y S Parmer University of Horticulture and Forestry, Nauni, Solan 173230, Himachal Pradesh, India 2 Department of Vegetable, Dr. Y S Parmer University of Horticulture and Forestry, Nauni, Solan 173230, Himachal Pradesh, India E-mail addresses: [email protected] [email protected] (S. Sharma).
(V.K.
Joshi),
The tremendous increase in consumers demand for fresh like products containing natural ingredients, changing food patterns and convenience has led to the development of minimally processed products using lactic acid bacterial (LAB) cultures. In the present studies, an attempt was made to develop and evaluate the appetizers from fermented vegetables. The vegetables were fermented using sequential culture of lactic acid bacteria viz., Lactobacillus plantarum (NCDC 020), Pediococcus cerevisiae (NCDC 038) and Streptococcus lactis var diacetylactis (NCDC 061) as per the conditions optimized earlier (Joshi et al., 2008; Sharma and Joshi, 2007). Different combinations of fermented vegetables viz., carrot, radish and cucumber with pear and mango pulps were made separately and were processed as per the routine practice (Vaidya and Vaidya, 2000). All the appetizers were prepared having a constant TSS of 45◦ B and different combinations of fermented pulp viz., 10, 20 and 30 with fruit pulps of mango, apricot and pear as per the respective combinations. A common recipe of appetizer was followed in their preparation. The titratable acidity of carrot, radish and cucumber based appetizers ranged from 1.12% to 1.72% in different appetizers. The blending ratio influenced the titratable acidity, brix-acid ratio, pH and colour of appetizer so prepared. Physico-chemical and sensory characteristics of all the appetizers prepared met the prescribed, specifications. Among various carrot and cucumber based appetizers, product prepared with fermented carrot only and the appetizer with blend of 10% fermented cucumber + 20% apricot were preferred to others. In the sensory quality evaluation, the fermented radish based appetizer having 20% radish + 10% apricot was rated the best. Out of the three vegetables and pulps, radish based appetizer having 20% radish + 10% apricot had the highest overall acceptability and was rated the best. The cost of production of fermented vegetable based appetizers was also economical. References Joshi, V.K., Sharma, Somesh, Thakur, N.S., 2008. Effect of temperature, salt, concentration and type of microorganism on lactic acid fermentation of carrot. Acta Alimentaria. 37 (2), 205–219. Sharma, Somesh, Joshi, V.K., 2007. Influence of temperature and salt concentration on lactic acid fermentation of radish (Raphnus sativus). J. Food Sci. Technol. 44 (6), 611–614.
Ruthaikongtaworn, Chidphong
Acetobacter xylinum was cultured in coconut medium (Punsri et al., 2003) and incubated in different conditions, static culture, shake culture and in a drum reactor. The oxygen transfer rate was determined by gassing out method (Stanbury et al., 1995). In the static culture, the coconut medium had the oxygen transfer rate of 2.65 × 10−4 mg oxygen/l min, while the shaking at 100 rpm and in a drum reactor which vertically rotating at 5 rpm in a rotating reactor had 0.2526 and 0.116 mg oxygen/l min, respectively. During fermentation, the dissolved oxygen in static culture was dropped sharply to unable to measure within the first day, while in rotating drum reactor the dissolved oxygen was gradually decreased and remained at about 0.1 mg/l after the fourth day of fermentation. The excessive dissolved oxygen in the liquid medium was found only in the shaking culture. The rotating drum reactor provided the heaviest pellicle wet weight and highest cellulose content at 36.20 g/100 ml and 0.57 g/100 ml media after 7 day incubation. The static culture and shake culture produced the same wet pellicle weight at about 28 g/100 ml but contained different in the amount of cellulose. From the results showed that the culture needed necessary amount of oxygen to produce cellulose. The excess amount of oxygen could take away the glucose for other metabolisms (Hwang et al., 1999) instead of cellulose production. The scanning electron micrographs (SEM) showed that the pellicles from static culture had the tightest fibril fabrication with biggest cells size. The shake culture pellicle had the smallest fibril with largest distance between fibrils. It also had capability to hold water less than pellicles from static and rotating drum reactor. References Hwang, J.W., Yang, Y.K., Hwang, J.K., Pyun, Y.R., Kim, Y.S., 1999. Effects of dissolved oxygen on cellulose production by Acetobacter xylinum BRC5 in agitated culture. J. Biosci. Bioeng. 88 (2), 183–188. Punsri, A., Tammarate, P., Krusong, W., Tantratian, S., 2003. The liquid/air interface area and depth of liquid medium suitable for cellulose production from Acetobacter sp. TISTR 975. J. Sci. Res. Chulalongkorn Univ. 28 (1), 35–43. Stanbury, P.F., Whitaker, A., Hall, S.J., 1995. Principle of Fermentation Technology. Pergamon Press, Oxford.
doi:10.1016/j.jbiotec.2008.07.1783