The use of partially purified laccase produced by some fungal isolates in aflatoxin B1 degradation

العناوين الأخرى

استخدام إنزيم اللاكيز المنقى جزئيا و المنتج من بعض العزلات الفطرية في تحطيم الافلاتوكسين B1

مقدم أطروحة جامعية

Abd Allah, Amnah Rami

مشرف أطروحة جامعية

al-Azami, Abd al-Karim Jasim Hashim

أعضاء اللجنة

Aziz, Ghazi Munim

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم التقانة الإحيائية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

Six fungal isolates have been evaluated for laccase production.

The isolates were subjected to two stages of screening process to select the highest extracellular laccase production.

It has been found that pleurotus sapidus had the highest productivity of the enzyme.

Optimization studies were done by the submerged culture medium and revealed that the glucose (1%) was the best carbon and L-asparagine (0.2%) was best nitrogen sources, at initial pH 5.5 and inoculum size 5 mm agar disk plug at 28°C for 5 days, using shaking incubator at 150 rpm.

Laccase activity reached up to 0.132 U/ml and specific activity was 3.77 U/mg.

Purification process included two steps dialysis using dialysis back and ion exchange chromatography using DEAE- cellulose, the purified enzyme had fold of purification about 3.14 times with 29.56% recovery.

Characterization experiments showed that: 1.

The optimum pH for the partially purified laccase activity was 6 and for stability was 6 too.

2.

The optimum temperature for enzyme activity was 55oC,the enzyme showed 100% of its activity after 1hr when incubated at temperature ranged (15-35) oC, then the activity decreased with increasing temperature at 85˚C, the enzyme retained 27% of the initial activity.

3.

The effect of incubation period at optimum pH and temperature in partially purified laccase stability was investigated, and the enzyme retained 60% of its activity after 24hr, and laccase activity became zero after 72 hr of incubation.

Summary II 4.

The effect of organic solvents on laccase activity was investigated.

The results showed that the maximum laccase activity detected with 10% methanol, and increasing the concentration of methanol up to 10% cause laccase activity inhibition.

Aflatoxin B1 degradation study showed that the remaining AFB1 was obtained using crude laccase was 0.208μg/ml while remaining AFB1 using partially purified laccase was 0.662 μg/ml after 72hr incubation and 150 rpm.

التخصصات الرئيسية

الأحياء

الموضوعات

• الكائنات الحية
• الفطريات
• الافلاتوكسينات

عدد الصفحات

93

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-600698