Enhanced secretion and low temperature stabilization of a hyperthermostable and Ca2+-independent α-amylase of Geobacillus thermoleovorans by surfactants

World J Microbiol Biotechnol

2006

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The optimization of cultural variables resulted in a marked enhancement in the secretion of cellulase-free and alkali-thermostable xylanase (EC 3.2.1.8) by an extreme thermophile Geobacillus thermoleovorans. The enzyme secretion was enhanced when the medium was supplemented with xylan (0.15%) and Tween-80 (0.1% v/v). In wheat brantryptone medium, the peak in enzyme production was attained within 42 h in a fermenter as compared to 72 h in shake flasks. Optimization of the culture conditions resulted in a 7.72-fold enhancement in enzyme production. The cellulase-free xylanase was optimally active at pH 8.5 and 80°C, and it was found to be useful in the pre-bleaching process of paper pulps.

Section: Xylanase Production (Ulmentioning

confidence: 77%

Alkali-thermostable and cellulase-free xylanase production by an extreme thermophile Geobacillus thermoleovorans

Sharma

Adhikari

World J Microbiol Biotechnol

2006

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“…Source and Maintenance of Strain G. thermoleovorans NP 54 was isolated from a water sample collected from the hot water spring of the Waimangu volcanic valley (New Zealand) and maintained as described earlier [26][27][28][29][30]. The culture is deposited at Microbial Type Culture Collection, Institute of Microbial Technology, Chandigarh (India; MTCC 4220).…”

Section: Methodsmentioning

confidence: 99%

“…Immobilization matrices and conditions must be selected for each microbial strain [24]. We have been publishing several research papers on production, purification, and characterization of α-amylase from G. thermoleovorans [25][26][27][28][29][30][31]. However, there is still a need to develop a sustainable enzyme titer and continuous culture of G. thermoleovorans by using immobilization, aerobic, and anaerobic fermentation processes; for that, the present investigation was undertaken to understand the nature of synthesis of Ca 2+ -independent, high maltose-forming, and hyperthermostable α-amylase in free as well as immobilized cells of G. thermoleovorans in aerobic and anaerobic fermentation.…”

mentioning

confidence: 99%

Hyperthermostable, Ca2+-Independent, and High Maltose-Forming α-Amylase Production by an Extreme Thermophile Geobacillus thermoleovorans: Whole Cell Immobilization

Rao

Appl Biochem Biotechnol

2009

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The synthesis of extracellular alpha-amylase in Geobacillus thermoleovorans was constitutive. The enzyme was secreted in metabolizable carbon sources as well as non-metabolizable synthetic analogues of glucose, but the titers were higher in the former than that in the latter. G. thermoleovorans is a fast-growing facultatively anaerobic bacterium that grows under both aerobic and anaerobic conditions and produces an extracellular amylolytic enzyme alpha-amylase with the by-product of lactic acid. G. thermoleovorans is a rich source of various novel thermostable biocatalysts for different industrial applications. alpha-Amylase synthesis was subject to catabolite repression in the presence of high concentrations of glucose. The addition of cAMP to the medium containing glucose did not result in the repression of alpha-amylase synthesis. The addition of maltose (1%) to the starch arginine medium resulted in a twofold enhancement in enzyme titers. Polyurethane foam (PUF)-immobilized cells secreted alpha-amylase, which was higher than that with the free cells. PUF appeared to be a better matrix for immobilization of the thermophilic bacterium than the other commonly used matrices. The repeated use of PUF-immobilized cells was possible over 15 cycles with a sustained alpha-amylase secretion. The use of this enzyme in starch saccharification eliminates the addition of Ca(2+) in starch liquefaction and its subsequent removal by ion exchangers from the product streams.

“…We have recently shown an extremely thermophilic bacterium Geobacillus thermoleovorans to secrete hyperthermostable, Ca 2+ -independent, and maltogenic α-amylase [9][10][11][12]. In this investigation, α-amylase of G. thermoleovorans was purified to homogeneity and characterized.…”

mentioning

confidence: 98%

Purification and Characterization of a Hyperthermostable and High Maltogenic α-Amylase of an Extreme Thermophile Geobacillus thermoleovorans

Rao

Appl Biochem Biotechnol

2007

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Synthetic dyes are released into the environment from textile industrial effluents. The discharge of this colored wastewater into rivers and lakes leads to a reduction in sunlight penetration in natural water bodies, which, in turn, decreases both photosynthetic activity and dissolved oxygen concentration and is toxic to living beings. Bacterial isolates are optimized for growth and biomass production before using them for decolorizing dye effluent. The bacterial isolates Bacillus sp. 1 and Bacillus sp. 2 were employed at different percentages by volume with standard nutrient concentration. Of these bacterial isolates Bacillus sp. 2 recorded maximum color reduction. The pH and electrical conductivity (EC) were reduced in the decolorized effluent, and a reduction in biologic oxygen demand, chemical oxygen demand, total suspended solids, and total dissolved solids (TDS) were also observed.