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      • KCI등재

        Enhanced Production of Cellobiase by a Marine Bacterium, Cellulophaga lytica LBH-14, in Pilot-Scaled Bioreactor Using Rice Bran

        Wa Cao(고와),Hung-Woo Kim(김형우),Jianhong Li(이잔홍),Jin-Woo Lee(이진우) 한국생명과학회 2013 생명과학회지 Vol.23 No.4

        본 연구의 목적은 통계학적 방법을 사용하여 해양미생물 Cellulophaga lytica LBH-14가 생산하는 cellobiase의 생산조건을 확립하는 것이었다. 이 균주의 생육에 최적인 미강, ammonium chloride 및 배지의 초기 pH는 100.0 g/l, 5.00 g/l 및 7.0이었으나, 이 균주가 생산하는 cellobiase의 생산에 최적인 조건은 각각 91.1 g/l, 9.02 g/l 및 6.6이었다. 이 균주의 생육에 최적인 K₂HPO₄, NaCl, MgSO₄?7H₂O 및 (NH₄)₂SO₄ 등과 같은 배지의 염농도는 각각 6.25, 0.62, 0.28 및 0.73 g/l이었으나, cellobiase 생산에 최적인 염들의 농도는 각각 4.46, 0.36, 0.27 및 0.73 g/l이었다. 또한, 균체의 생육 및 cellobiase의 생산에 최적인 온도는 각각 35 및 25℃이었다. 플라스크 규모에서 최적화한 조건으로 파이롯트 규모의 생물배양기에서 cellobiase를 생산한 결과, 이 균주가 생산하는 cellobiase의 생산성은 92.3 U/ml이었으며, 이는 최적화하기 전에 비하여 5.4배 향상된 것 이었다. 본 연구를 통하여 쌀 도정공정의 부산물인 미강 및 ammonium chloride를 cellobiase를 생산하는 기질로 개발하였으며 해양 미생물을 사용하여 cellobiase의 생산기간을 7일에서 3일로 단축시켰다. 또한, 본 연구를 통하여 C. lytica LBH-14가 생산하는 cellobiase의 최적 생산조건은 이 균주가 생산하는 CMCase의 최적 생산조건과 다르다는 사실을 확인하였다. The aim of this work was to establish the optimal conditions for the production of cellobiase by a marine bacterium, Cellulophaga lytica LBH-14, using response-surface methodology (RSM). The optimal conditions of rice bran, ammonium chloride, and the initial pH of the medium for cell growth were 100.0 g/l, 5.00 g/l, and 7.0, respectively, whereas those for the production of cellobiase were 91.1 g/l, 9.02 g/l, and 6.6, respectively. The optimal concentrations of K₂HPO₄, NaCl, MgSO₄·7H2O, and (NH₄)₂SO₄ for cell growth were 6.25, 0.62, 0.28, and 0.42 g/l, respectively, whereas those for the production of cellobiase were 4.46, 0.36, 0.27, and 0.73 g/l, respectively. The optimal temperatures for cell growth and for the production of cellobiase by C. lytica LBH-14 were 35 and 25℃, respectively. The maximal production of cellobiase in a 100 L bioreactor under optimized conditions in this study was 92.3 U/ml, which was 5.4 times higher than that before optimization. In this study, rice bran and ammonium chloride were developed as carbon and nitrogen sources for the production of cellobiase by C. lytica LBH-14. The time for the production of cellobiase by the marine bacterium with submerged fermentations was reduced from 7 to 3 days, which resulted in enhanced productivity of cellobiase and a decrease in its production cost. This study found that the optimal conditions for the production of cellobiase were different from those of CMCase by C. lytica LBH-14.

      • KCI등재

        In situ Reversible Aggregation of Extracellular Cellobiase in the Filamentous Fungus Termitomyces clypeatus

        Samudra Prosad Banik,Swagata Pal,Shakuntala Ghorai,Sudeshna Chowdhury,Rajib Majumder,Soumya Mukherjee,Suman Khowala 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.5

        Cellobiase (E.C. 3.2.1.21), is a widely exploited industrial glycosidase with a major role in biofuel industry. Its stability and shelf life are major bottlenecks in achieving a superior formulation for industry. In the filamentous fungus Termitomyces clypeatus, the enzyme is secreted in a co-aggregated form with sucrase; the separation of this co-aggregation results in substantial loss of the enzyme’s activity. The aim of the present study was to examine the mode of aggregation of the secreted cellobiase-sucrase coaggregate and its role in the stabilization of cellobiase. Transmission electron microscopy and dynamic light scattering of purified co-aggregates revealed reversible, concentration driven self-aggregation of the extracellular enzymes to form larger entities. However, the intracellular enzyme aggregates were rigid,non-interacting, and possessed a higher percentage of disulphide bonds. Circular dichroic spectra of the two coaggregates indicated no significant difference in secondary structures. Self-association increased the stability of extracellular aggregates towards heat by 1.5 fold, SDS by 4 ~ 7 fold, and chaotropic agents, by 1.5 ~ 2 fold, than the intracellular counterpart. The Km of extracellular aggregate varied between 0.29 and 0.45 mM as a result of spontaneous aggregation and disaggregation, whereas that of intracellular aggregate was 0.22 mM irrespective of its concentration status. In situ detection of cellobiase in native PAGE revealed two activity bands of the extracellular enzyme, which indicated a minimum of two active dissociated aggregate species, as compared to a single band for the intracellular enzyme. These studies are believed to improve the understanding of aggregation of the fungal glycosidases, which remains to be a blackbox, to increase the efficacy of these enzymes. Cellobiase (E.C. 3.2.1.21), is a widely exploited industrial glycosidase with a major role in biofuel industry. Its stability and shelf life are major bottlenecks in achieving a superior formulation for industry. In the filamentous fungus Termitomyces clypeatus, the enzyme is secreted in a co-aggregated form with sucrase; the separation of this co-aggregation results in substantial loss of the enzyme’s activity. The aim of the present study was to examine the mode of aggregation of the secreted cellobiase-sucrase coaggregate and its role in the stabilization of cellobiase. Transmission electron microscopy and dynamic light scattering of purified co-aggregates revealed reversible, concentration driven self-aggregation of the extracellular enzymes to form larger entities. However, the intracellular enzyme aggregates were rigid,non-interacting, and possessed a higher percentage of disulphide bonds. Circular dichroic spectra of the two coaggregates indicated no significant difference in secondary structures. Self-association increased the stability of extracellular aggregates towards heat by 1.5 fold, SDS by 4 ~ 7 fold, and chaotropic agents, by 1.5 ~ 2 fold, than the intracellular counterpart. The Km of extracellular aggregate varied between 0.29 and 0.45 mM as a result of spontaneous aggregation and disaggregation, whereas that of intracellular aggregate was 0.22 mM irrespective of its concentration status. In situ detection of cellobiase in native PAGE revealed two activity bands of the extracellular enzyme, which indicated a minimum of two active dissociated aggregate species, as compared to a single band for the intracellular enzyme. These studies are believed to improve the understanding of aggregation of the fungal glycosidases, which remains to be a blackbox, to increase the efficacy of these enzymes.

      • KCI등재

        Enhanced Production of Cellobiase by Marine Bacterium Cellulophaga lytica LBH-14 from Rice Bran under Optimized Conditions Involved in Dissolved Oxygen

        Wa Gao,정정한,Jianghong Li,이진우 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.1

        The optimal conditions for production ofcellobiase by C. lytica LBH-14 at flask scale had beenpreviously reported. In this study, parameters involved indissolved oxygen in 7 and 100 L bioreactors were optimizedfor pilot-scale production of cellobiase. The optimalagitation speed and aeration rate for cell growth of C. lyticaLBH-14 were 400 rpm and 1.11 vvm in a 7 L bioreactor,whereas those for production of cellobiase were 330 rpmand 0.70 vvm. The analysis of variance (ANOVA) impliedthat significant factor for cell growth was the aeration rate,whereas those for production of cellobiase were theaeration rate as well as the agitation speed. The optimalinner pressures for cell growth and production of cellobiaseby C. lytica LBH-14 in a 100 L bioreactor were 0.00 and0.06 MPa, respectively. The maximal production of cellobiasein a 100 L bioreactor under optimized conditions using ricebran was 140.1 U/mL, which was 1.52 times higher thanthat in a flask scale.

      • KCI등재

        Enhanced Production of Cellobiase by a Marine Bacterium, Cellulophaga lytica LBH-14, in Pilot-Scaled Bioreactor Using Rice Bran

        Wa Cao,김훙우,Jianhong Li,이진우 한국생명과학회 2013 생명과학회지 Vol.24 No.4

        The aim of this work was to establish the optimal conditions for the production of cellobiase by a marine bacterium, Cellulophaga lytica LBH-14, using response-surface methodology (RSM). The optimal conditions of rice bran, ammonium chloride, and the initial pH of the medium for cell growth were 100.0 g/l, 5.00 g/l, and 7.0, respectively, whereas those for the production of cellobiase were 91.1 g/l, 9.02 g/l, and 6.6, respectively. The optimal concentrations of K2HPO4, NaCl, MgSO4∙7H2O, and (NH4)2SO4 for cell growth were 6.25, 0.62, 0.28, and 0.42 g/l, respectively, whereas those for the production of cellobiase were 4.46, 0.36, 0.27, and 0.73 g/l, respectively. The optimal temperatures for cell growth and for the production of cellobiase by C. lytica LBH-14 were 35 and 25℃, respectively. The maximal production of cellobiase in a 100 L bioreactor under optimized conditions in this study was 92.3 U/ml, which was 5.4 times higher than that before optimization. In this study, rice bran and ammonium chloride were developed as carbon and nitrogen sources for the production of cellobiase by C. lytica LBH-14. The time for the production of cellobiase by the marine bacterium with submerged fermentations was reduced from 7 to 3 days, which resulted in enhanced productivity of cellobiase and a decrease in its production cost. This study found that the optimal conditions for the production of cellobiase were different from those of CMCase by C. lytica LBH-14.

      • KCI등재

        Evidence of an Alternative Route of Cellobiase Secretion in the Presence of Brefeldin A in the Filamentous Fungus Termitomyces clypeatus

        ( Banik Samudra Prosad ),( Swagata Pal ),( Sudeshna Chowdhury ),( Shakuntala Ghorai ),( Suman Khowala ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.4

        Secretion of cellobiase occurred in a brefeldin A (BFA) uninhibited manner in the filamentous fungus Termitomyces clypeatus. Fluorescence confocal microscopy revealed that application of the drug at a concentration of 50 μg/ml caused arrest of Spitzenkorper assembly at the hyphal tip. This resulted in greater than 30% inhibition of total protein secretion in the culture medium. However, the cellobiase titer increased by 17%, and an additional 13% was localized in the vacuolar fraction en route secretion. The secretory vacuoles formed in the presence of the drug were also found to be bigger (68 nm) than those in the control cultures (40 nm). The enzyme secreted in the presence and absence of BFA revealed a single activity band in both cases in native PAGE and had similar molecular masses (approx. 120 kDa) in SDS-PAGE. The BFA enzyme retained 72% of native glycosylation. It also exhibited a higher stability and retained 98% activity at 50oC, 93.3% activity at pH 9, 63.64% activity in the presence of 1M guanidium hydrochloride, and 50% activity at a glucose concentration of 10 mg/ml in comparison to 68% activity, 75% activity, 36% activity, and 19% activity for the control enzyme, respectively. The observations collectively aimed at the operation of an alternative secretory pathway, distinct from the target of brefeldin A, which bypassed the Golgi apparatus, but still was able to deliver the cargo to the vacuoles for secretion. This can be utilized in selectively enhancing the yield and stability of glycosidases for a successful industrial recipe.

      • KCI등재

        Purification and Biochemical Properties of a Glucose-Stimulated β-D-Glucosidase Produced by Humicola grisea var. thermoidea Grown on Sugarcane Bagasse

        Cesar Vanderlei Nascimento,Flávio Henrique Moreira Souza,Douglas Chodi Masui,Francisco Assis Leone,Rosane Marina Peralta,João Atílio Jorge,Rosa Prazeres Melo Furriel 한국미생물학회 2010 The journal of microbiology Vol.48 No.1

        The effect of several carbon sources on the production of mycelial-bound β-glucosidase by Humicola grisea var. thermoidea in submerged fermentation was investigated. Maximum production occurred when cellulose was present in the culture medium, but higher specific activities were achieved with cellobiose or sugarcane bagasse. Xylose or glucose (1%) in the reaction medium stimulated β-glucosidase activity by about 2-fold in crude extracts from mycelia grown in sugarcane bagasse. The enzyme was purified by ammonium sulfate precipitation, followed by Sephadex G-200 and DEAE-cellulose chromatography, showing a single band in PAGE and SDS-PAGE. The β-glucosidase had a carbohydrate content of 43% and showed apparent molecular masses of 57 and 60 kDa, as estimated by SDS-PAGE and gel filtration, respectively. The optimal pH and temperature were 6.0 and 50°C, respectively. The purified enzyme was thermostable up to 60 min in water at 55°C and showed half-lives of 7 and 14 min when incubated in the absence or presence of 50 mM glucose, respectively, at 60°C. The enzyme hydrolyzed p-nitrophenyl-β-D-glucopyranoside, p-nitrophenyl-β-Dgalactopyranoside,p-nitrophenyl-β-D-fucopyranoside, p-nitrophenyl-β-D-xylopyranoside, o-nitrophenyl-β-Dgalactopyranoside,lactose, and cellobiose. The best synthetic and natural substrates were p-nitrophenyl-β-Dfucopyranoside and cellobiose, respectively. Purified enzyme activity was stimulated up to 2-fold by glucose or xylose at concentrations from 25 to 200 mM. The addition of purified or crude β-glucosidase to a reaction medium containing Trichoderma reesei cellulases increased the saccharification of sugarcane bagasse by about 50%. These findings suggest that H. grisea var. thermoidea β-glucosidase has a potential for biotechnological applications in the bioconversion of lignocellulosic materials.

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