الفهرس 
Lignin degrading enzymesOnly 14 pages are availabe for public view
 |  | from | 214 |  |  |
| | | from | 214 | | |
Abstract
The ability of fungi to degrade lignocellulosic biomass can be exploited to produce lignocellulolytic enzymes and potentially bio-degrade recalcitrant polymer compounds. The current study was investigated for ligninolytic enzymes production utilizing agricultural and agro-industrial residues under solid state fermentation. Twenty-seven fungi were isolated, then purified, identified and screened for their ligninolytic potential. In addition to the isolated fungi, two fungal species Ganoderma lucidum and lentinula edodes (white rot fungi) were purchased from Mushroom Laboratory Culture Collection (MLCC), El-Giza Governorate, Egypt. Out of the total twenty-nine tested fungi, only three fungal species Ganoderma lucidum, Lentinula edodes and Trichoderma harzianum isolate (2) demonstrated ligninolytic activity. Out of the three ligninolytic fungal species, G. lucidum exhibited the highest producer for the total ligninolytic enzymes. The definition of G. lucidum was confirmed genetically by sequencing of ITS region of fungal rDNA and has accession number ON972439 in Gene Bank. Amongst the different ten agro-industrial and agricultural residues screened, wheat bran (WB) was the most utilized by G. lucidum for producing laccase enzyme laccase. During the optimization of culture conditions, laccase activity increased by 1.7 fold. The highest activity of laccase was (1.602 U/ml) obtained under optimized culture conditions (incubation period 7 days, temperature, 30 °C, pH 5, moisture content 75% v/w, inoculum size 5 ml of spore suspension (107 spores/ml). The laccase enzyme produced was partially purified by ammonium sulphate precipitation (80%) followed by dialysis. Laccase enzyme purification finding indicated (3.76) fold purity enhancements. Specific activity of partially purified laccase was 3.16 U/mg protein and final yield of 58.52%.