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Optimization of Industrial Conditions for Catalase Production by Thermoascus Aurantiacus WSH 03-01 and Its Application in the Textile Cleaner Production

Author: LuGuoJun
Tutor: HuaZhaoZhe
School: Jiangnan University
Course: Environmental Engineering
Keywords: Catalase DO Stage Control Add mixed Ethanol Industrial production Reactive oxygen stress
CLC: TS190
Type: Master's thesis
Year: 2008
Downloads: 165
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Abstract

Catalase (Catalase, abbreviated CAT), is present in all aerobic microorganisms and animal and plant cells, catalytic H ₂ O ₂ is decomposed into H ₂ O and O ₂, in the food disinfection, clinical analysis, medical diagnosis, and textiles, paper, pulp and other industries to be more widely applied. As people's awareness of the environmental, catalase began substitute for fabric washing and bleaching processes in chemical reagents reduction method to remove H ₂ O ₂, is a green , clean, efficient biocatalyst. However, most products can not tolerate the bleaching bath CAT harsh conditions and therefore a need to develop at a high temperature (gt; 60 ℃) and alkaline (pH gt; 9) the enzyme is stable under the conditions, and the Thermophilic aurantiacus Thermoascus aurantiacus WSH 03-01BC produced by CAT and enzyme products on the market today compared to its heat resistance, alkali resistance to better meet the requirements of the textile dyeing process. In this thesis, a thermophilic ascomycete Thermoascus aurantiacus WSH 03-01BC as starting strain studied fermentation process improvement and environmental factors on the impact of bacterial synthesis of CAT, and for the memory cells in glucose catabolite repression phenomena contact their the relationship between the metabolism of ethanol and found to add ethanol (75%) to promote favorable law CAT synthesis. In addition, the strain produced by a simple performance of the crude enzyme CAT, research on the application, and the effect on cell growth and the active oxygen producing mechanism of the enzyme in. The main contents are as follows: 1. Because T. aurantiacus WSH 03-01BC aurantiacus enzyme at different stages of fermentation dissolved oxygen requirements for different phases dissolved oxygen level control cell growth and help to improve the level of CAT synthesis. Fermentation 0 ^{4 8h control DO concentration of 80% (volume fraction), cell growth reached the maximum amount of DCW 10.53g / L, compared with the control (10.09g / L) increased by 4.4%; in Fermentation 48h ~ 72h controls DO level of 50% (v / v), bacterial catalase synthesis maximum 2837U/ml, compared to the control (1887U/ml) 50.34% increase. 2. T. aurantiacus WSH 03-01BC aurantiacus is an obligate thermophilic bacteria, experiments show that its optimum growth temperature and optimum temperature for enzyme production is inconsistent. Phased controlled fermentation strategy allows the cell growth temperature sufficient to further promote the premise of a large number of bacterial catalase synthesis. Fermentation 0h ~ 36h fermentation temperature control 46 ℃, the temperature at 36h ~ 72h constant at 49 ℃, the growth reached 10.79g / L, the maximum activity reached 2875U/mL, unit cell enzyme production capacity reached 278.86U/mg, with a single control fermentation temperature is 46 ℃, the maximum enzyme activity, respectively, compared increased by 28.9% and 29.9%. 3 add the appropriate amount of ethanol (75%) can promote bacterial synthesis of catalase, when adding the total over 2.4%, the cell growth and enzyme production are subject to greater inhibition. In the fermentation 36 ^{4 8h, constant stream plus one add the same amount of ethanol than ethanol contribute more effectively to bacterial enzyme production. In the early period of cell growth and the stability of the constant flow plus 1.6% ethanol and mixed with 0.4% of the H ₂ O ₂, catalase production was increased by 50.1 %. 4 on the basis of preliminary studies, the experimental results amplified to 1 m3 and 5 m3 tank when the pilot scale, 1 m3 and 5 m3 tank and production intensity activity reached 2224 U / mL; 9267U / L · h and 2300U/mL; 13938U / L · h, respectively, close to and above 7 L tank level, indicating that the amplification method used and thus determine the amount of aeration and agitation speed is reasonable, and the actual trial production results show that the use T. aurantiacus WSH 03-01 BC CAT for industrial production is entirely feasible. 5. T. aurantiacus WSH 03-01BC CAT crude enzyme produced by the characteristics of studies have shown that the thermal stability of the enzyme higher temperature range is 60 ℃ ^{8 0 ℃, pH scope 9 to 11, and its tolerance to high temperatures and strong alkaline environment characteristics in the textile industry will have broad application prospects. 6. Improve the dissolved oxygen concentration in the environment can promote T. aurantiacus WSH 03-01BC growth, but high oxygen concentration cell caused O ₂ - Stress stress level is not high, the performance increase dissolved oxygen concentration (50% -80%) when the CAT activity did not significantly increase. In menadione (flow acceleration 3μM · h-1) in the presence of and improve dissolved oxygen concentration allows cells to O ₂ - Stress stress levels are increased, the performance improved when the dissolved oxygen concentration to 50%, SOD and CAT activity reached 12.11U/mg and 3200U/mL, compared with the 25% level, respectively, increased by 18.6% and 17.3%; when DO continue to increase to 80%, the maximum SOD activity Up 12U/mg, but the maximum CAT activity (2889U/ml) compared with the 50% level but decreased 10.8%. Comparison of cell growth, and this may be due to oxidative damage to cells caused by too high a.}}}

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