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Acid-sensitive Lactobacillus plantarum as starter to reduce post-acidification in a traditional Thai fermented sausage
Abstracts / Journal of Bioscience and Bioengineering 108 (2009) S114–S134 References 1. Ishii, S., Koki, J., Unno, H., and Hori, K.: Two morphological types of cell appendages on a strongly adhesive bacterium, Acinetobacter sp. strain Tol 5, Appl. Environ. Microbiol., 70, 5026-5029 (2004). 2. Ishii, S., Unno, H., Miyata, S., and Hori, K.: Effect of cell appendages on the adhesion properties of a highly adhesive bacterium, Acinetobacter sp. Tol 5. Biosci. Biotechnol. Biochem., 70, 2635-2640 (2006). 3. Cotter, S. E., Surana, N. K., and St Geme, J. W. 3rd.: Trimeric autotransporters: a distinct subfamily of autotransporter proteins, Trends Microbiol., 13, 199-205. (2005). doi:10.1016/j.jbiosc.2009.08.341
FM-O8 Acid-sensitive Lactobacillus plantarum as starter to reduce post-acidification in a traditional Thai fermented sausage Peter Kurdi,1 Pornpan Jaichumjai,2 and Ruud Valyasevi1 Food Biotechnology Lab, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani, Thailand 1 and Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand 2 The aim of this study was to derive new starter culture variants that are unable to grow below pH 4.6, which is the desired product pH of the traditional Thai fermented pork sausage, Nham, and apply them in Nham fermentation. Several acid-sensitive mutants of one of the commercial Nham starter cultures, Lactobacillus plantarum BCC 9546, were isolated as spontaneous neomycin-resistant mutants. The growth of three representative mutants were characterized in MRS broth, which revealed that their cell numbers were 3.7–4.9 times less and produced about 50 % less acid after 48 h. At the same time their culture pHs were about 0.6–0.7 pH unit higher than that of the parental strain, although only one mutant strain could maintain this culture pH difference after 72 h. The H+-ATPase activities of the three mutants were found significantly lower than that of the parent under either neutral or acidic conditions. Consequently, internal pH values of the mutants appeared to be lower, especially in acidic environment (pH 5). When the most acid sensitive mutant was applied in experimental Nham production as starter culture its cell number in Nham was comparable to that of the parent strain during the fermentation. Nham fermented with the mutant had significantly higher pH at the end of fermentation (3 days) than that of fermented by the parent strain. Moreover, after an additional 4 days of fermentation in ambient temperature (30 °C) the pH of Nham fermented with the mutant was still found significantly higher than that of the ones fermented by the parent strain. These results indicate that the use of acid-sensitive L. plantarum as starter culture can reduce the severity of post-acidification and increase the shelf life of Nham at ambient temperature. doi:10.1016/j.jbiosc.2009.08.342
FM-O9 PPFD alteration and cellular filtration for large scale biomass production of Chlorella vulgaris Buitenzorg Anondho Wijanarko, and Dianursanti Priyambodo University of Indonesia, Kampus UI, Depok, West Java, Indonesia Chlorella vulgaris Buitenzorg's CO2 fixation and biomass production has been carried out for reducing global warming that caused increasing
S117
of CO2 level in the atmosphere. This research used prototype photobioreactors for large scale biomass production at alteration PPFD (Photosynthetic Photon Flux Density) or using glassy sponge filter at constant PPFD. Chlorella was grown in 18.0 dm3 Benneck medium in bubble-column(38.5 cm× 10 cm× 60 cm). Operation conditions, Temperature(T) 29.0 °C; Pressure(P) 1 atm.; superficial gas velocity(UG) 15.7 m/h; CO2 concentration(yCO2i) in sparged bubble air 10.0%. This photobioreactor are illuminated by 20 W Halogen lamp that run at alteration PPFD and constant PPFD using filter; as method to keep photon energy density(E) in cellular culture constant. To minimize shelf shading effect that was caused by increasing microalgae density(Xf) during cultivation period and also to keep E constant, increasing PPFD (Ii = Iμmax,opt) needs to keep maximum specific growth rate (μmax) [1]. At beginning, Ii was set at 74.4 mmol/(m2 s) and adjusted depend on culture cell density to maintain μmax still remained high that resulted a relation Xf and Iμmax,opt which was needed for keeping μmax [2]. Similar to result in 0.200 dm3 reactor, at alteration PPFD shown higher Xf than at constant PPFD of 74.4 μmol/(m2 s). During 160 h at alteration PPFD, Xf was around 2.4 times compared to constant PPFD during 300 h. Cellular cultivation using filter at constant PPFD of 74.4 μmol/(m2.s), produced higher Xf than cultivation without filter. During 200 h cultivation period using filter, Xf was around 2.5 times compare to result during 296 h without it. This result concluded that both of alteration and constant PPFD using filter have similar effect for increasing Xf and shelf-shading effect during cell cultivation could be decreased by using filter. References 1. Hirata S., Taya, M., and Tone, S.: Characterization of Chlorella Cell Cultures in Batch and Continuous Operations under a Photoautotrophic Condition. J. Chem. Eng. Japan, 29, 953-959 (1996). 2. Wijanarko, A., Dianursanti, Sendjaya, A.Y., Hermansyah, H., Witarto, A.B., Gozan, M., Sofyan, B.T., Asami, K., Ohtaguchi, K., Soemantojo, R.W., and Song, S.K.: Enhanced Chlorella vulgaris Buitenzorg Growth by Photon Flux Density Alteration in Serial Photobioreactors. Biotechnol. Bioprocess Eng., 13, 476-482 (2008). doi:10.1016/j.jbiosc.2009.08.343
FM-O10 Hydrogen and ethanol production from bio-diesel waste containing high concentration of glycerol using newly isolated Enterobacter aerogenes HU201 Yutaka Nakashimada, Tomofumi Kikuzaki, and Naomichi Nishio Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan In previous study, we reported that hydrogen and ethanol was simultaneously produced by Enterobacter aerogenes HU101 from biodiesel fuel (BDF) wastes containing glycerol as carbon source (1). However, the optimum concentration of glycerol for hydrogen and ethanol production of this strain was only 10 g/L, which was much lower than that in original wastes (ca. 500 g/L). Therefore, in this study, we newly isolated a microorganism from soil sample that was able to grow in BDF waste with lower dilution. High BDF wastes tolerant microorganisms were screened from several soil samples on the agar plate containing BDF wastes diluted to 50 g/L glycerol with synthetic medium. After several attempts, a facultative anaerobic bacterium was selected as the candidate. The microorganism was identified as Enterobacter aerogenes HU201 that was closely related to E. aerogenes HU101. In batch cultures of HU201 using a serum-bottle, the optimum condition of glycerol concentration and initial pH for ethanol production was the range of 300–500 mM and 7.0, respectively. However, pH decreased to 5.8 from 7.0 in batch culture, leading to
FM-O8 Acid-sensitive Lactobacillus plantarum as starter to reduce post-acidification in a traditional Thai fermented sausage Peter Kurdi,1 Pornpan Jaichumjai,2 and Ruud Valyasevi1 Food Biotechnology Lab, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathumthani, Thailand 1 and Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand 2 The aim of this study was to derive new starter culture variants that are unable to grow below pH 4.6, which is the desired product pH of the traditional Thai fermented pork sausage, Nham, and apply them in Nham fermentation. Several acid-sensitive mutants of one of the commercial Nham starter cultures, Lactobacillus plantarum BCC 9546, were isolated as spontaneous neomycin-resistant mutants. The growth of three representative mutants were characterized in MRS broth, which revealed that their cell numbers were 3.7–4.9 times less and produced about 50 % less acid after 48 h. At the same time their culture pHs were about 0.6–0.7 pH unit higher than that of the parental strain, although only one mutant strain could maintain this culture pH difference after 72 h. The H+-ATPase activities of the three mutants were found significantly lower than that of the parent under either neutral or acidic conditions. Consequently, internal pH values of the mutants appeared to be lower, especially in acidic environment (pH 5). When the most acid sensitive mutant was applied in experimental Nham production as starter culture its cell number in Nham was comparable to that of the parent strain during the fermentation. Nham fermented with the mutant had significantly higher pH at the end of fermentation (3 days) than that of fermented by the parent strain. Moreover, after an additional 4 days of fermentation in ambient temperature (30 °C) the pH of Nham fermented with the mutant was still found significantly higher than that of the ones fermented by the parent strain. These results indicate that the use of acid-sensitive L. plantarum as starter culture can reduce the severity of post-acidification and increase the shelf life of Nham at ambient temperature. doi:10.1016/j.jbiosc.2009.08.342
FM-O9 PPFD alteration and cellular filtration for large scale biomass production of Chlorella vulgaris Buitenzorg Anondho Wijanarko, and Dianursanti Priyambodo University of Indonesia, Kampus UI, Depok, West Java, Indonesia Chlorella vulgaris Buitenzorg's CO2 fixation and biomass production has been carried out for reducing global warming that caused increasing
S117
of CO2 level in the atmosphere. This research used prototype photobioreactors for large scale biomass production at alteration PPFD (Photosynthetic Photon Flux Density) or using glassy sponge filter at constant PPFD. Chlorella was grown in 18.0 dm3 Benneck medium in bubble-column(38.5 cm× 10 cm× 60 cm). Operation conditions, Temperature(T) 29.0 °C; Pressure(P) 1 atm.; superficial gas velocity(UG) 15.7 m/h; CO2 concentration(yCO2i) in sparged bubble air 10.0%. This photobioreactor are illuminated by 20 W Halogen lamp that run at alteration PPFD and constant PPFD using filter; as method to keep photon energy density(E) in cellular culture constant. To minimize shelf shading effect that was caused by increasing microalgae density(Xf) during cultivation period and also to keep E constant, increasing PPFD (Ii = Iμmax,opt) needs to keep maximum specific growth rate (μmax) [1]. At beginning, Ii was set at 74.4 mmol/(m2 s) and adjusted depend on culture cell density to maintain μmax still remained high that resulted a relation Xf and Iμmax,opt which was needed for keeping μmax [2]. Similar to result in 0.200 dm3 reactor, at alteration PPFD shown higher Xf than at constant PPFD of 74.4 μmol/(m2 s). During 160 h at alteration PPFD, Xf was around 2.4 times compared to constant PPFD during 300 h. Cellular cultivation using filter at constant PPFD of 74.4 μmol/(m2.s), produced higher Xf than cultivation without filter. During 200 h cultivation period using filter, Xf was around 2.5 times compare to result during 296 h without it. This result concluded that both of alteration and constant PPFD using filter have similar effect for increasing Xf and shelf-shading effect during cell cultivation could be decreased by using filter. References 1. Hirata S., Taya, M., and Tone, S.: Characterization of Chlorella Cell Cultures in Batch and Continuous Operations under a Photoautotrophic Condition. J. Chem. Eng. Japan, 29, 953-959 (1996). 2. Wijanarko, A., Dianursanti, Sendjaya, A.Y., Hermansyah, H., Witarto, A.B., Gozan, M., Sofyan, B.T., Asami, K., Ohtaguchi, K., Soemantojo, R.W., and Song, S.K.: Enhanced Chlorella vulgaris Buitenzorg Growth by Photon Flux Density Alteration in Serial Photobioreactors. Biotechnol. Bioprocess Eng., 13, 476-482 (2008). doi:10.1016/j.jbiosc.2009.08.343
FM-O10 Hydrogen and ethanol production from bio-diesel waste containing high concentration of glycerol using newly isolated Enterobacter aerogenes HU201 Yutaka Nakashimada, Tomofumi Kikuzaki, and Naomichi Nishio Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan In previous study, we reported that hydrogen and ethanol was simultaneously produced by Enterobacter aerogenes HU101 from biodiesel fuel (BDF) wastes containing glycerol as carbon source (1). However, the optimum concentration of glycerol for hydrogen and ethanol production of this strain was only 10 g/L, which was much lower than that in original wastes (ca. 500 g/L). Therefore, in this study, we newly isolated a microorganism from soil sample that was able to grow in BDF waste with lower dilution. High BDF wastes tolerant microorganisms were screened from several soil samples on the agar plate containing BDF wastes diluted to 50 g/L glycerol with synthetic medium. After several attempts, a facultative anaerobic bacterium was selected as the candidate. The microorganism was identified as Enterobacter aerogenes HU201 that was closely related to E. aerogenes HU101. In batch cultures of HU201 using a serum-bottle, the optimum condition of glycerol concentration and initial pH for ethanol production was the range of 300–500 mM and 7.0, respectively. However, pH decreased to 5.8 from 7.0 in batch culture, leading to