BEYAZ-ÇÜRÜKÇÜL FUNGUSLARIN SELÜLAZ VE KSİLANAZ ENZİM ÜRETİM POTANSİYELLERİNİN ARAŞTIRILMASI
Thesis Type: Doctorate
Institution Of The Thesis: İnönü Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2013
Thesis Language: Turkish
Student: DEMET DOĞAN
Principal Supervisor (For Co-Supervisor Theses): SİBEL KAHRAMAN
Open Archive Collection: AVESIS Open Access Collection
Abstract:The white rot fungi produce a wide range of extracellular lignocellulosic enzymes including: xylanases, cellulases and laccases. Large quantities of agricultural wastes accumulate in the environment can be used for the production of lignocellulosic enzymes. Cotton stalks are available in vast quantities in all cotton-growing countries such as Turkey as local agricultural waste and these wastes can be used to stimulate lignocellulosic enzyme production. The objective of the present study is to increase the xylanase and cellulase production of white rot fungi using inexpensive and abundantly available agro-residues thereby reducing the cost of enzyme production in different synthetic and natural culture media (Olive Oil Mill Wastewater-OOMW). In the present study, two white-rot fungal species P. ostreatus and newly isolated P. ostreatus were examined for their ability to produce cellulase, xylanase on cotton stalk waste at synthetic and natural culture media. Different cultural conditions were investigated to assess their effect in optimizing enzyme production. For optimization of enzyme production, the parameters studied were incubation time (3-6-9-12-15 days), temperature (20-30-40-50 °C), pH (3.0-5.0-7.0-9.0), amount of cotton stalk (0.1-0.5-1.0 gr), particle size of cotton stalk (small-large). The results indicated that various factors including temperature, pH, incubation time, agitation rate, cotton stalk amount and cotton stalk particle size influence xylanase and cellulase production. Optimum temperature and pH of the synthetic and natural medium for the cellulase and xylanase production by P. ostreatus were 30-40 °C and pH 3-5, whereas those for the production of cellulase and xylanase by newly isolated P. ostreatus were 30-40 °C and pH 5-7. The results showed that as the amount and size of cotton stalk was increased, cellulase and xylanase production increased accordingly. The optimal incubation time for enzymes production by either fungi was 3-6 days. In other part of this study, further experiments were conducted in order to determined effect of different agricultural wastes (other than cotton stalk) on enzymatic activity. For this purpose, cellulase and xylanase enzyme activities of two white rot fungi were determined in culture media containing agricultural wastes such as wheat straw, corn cobs, pine cone and aspen shavings. Experimental results show that, wheat straw and corn cobs were more effective enzyme inductor than pine cone and aspen shaving. In last part of this study, color removal (%) of OOMW by these fungi were determined. According to the results, under the optimum conditions, P. ostreatus removed approximately 97.08 % color and newly isolated P. ostreatus removed approximately 97.81 % color of OOMW used. The results of this study demonstrated that it is possible to obtain high amounts of cellulase and xylanase by using P. ostreatus isolates under optimal conditions. KEYWORDS: Cellulase, xylanase, white rot fungi, cotton stalk, agricultural wastes