Abstract
Exploration of microbial communities for the synthesis of chitinolytic enzymes is an important characteristic in biodiversity. Chitinolytic microbial species can be used for degradation of chitin instead of chemical treatment, which has lesser environmental impact because of its ecofriendly. The filtrate of twenty fungal isolates was tested for nematode mortality using root-knot nematode Meloidogyne incognita larvae. The isolate HA4 gave the highest mortality percentage (97% mortality). HA4 was selected and identified on molecular basis using ITS rDNA genes as Aspergillus terreus TNS05 (LC57100). The maximum dry biomass was gained on medium 6 (10.7 g l(-1)) and the final pH reach its maximum value on medium 2 (7.8) and the lowest was attained in medium 2 (5.1). The highest value of economic coefficient (Ec) (73.9%) was detected in medium 7. The highest chitinase activity was observed in medium 7 (9.4 U ml(-1)) and the least activity (0.2 U ml(-1)) was obtained in medium 14. By calculating each factor individually, the highest chitinase activity was attained at chitin (1.0 g%), urea (0.75 g%), yeast extract (2.2 g%), ammonium sulfate (2.5 g%), potassium dihydrogen phosphate (4.5 g%) at agitation rate (250 rpm) and pH value (6.0). By comparing to the different media composition confirmed that medium 7 is the best medium for chitinase activity. The highest biomass protein content was attained in medium 16 (932.4 mg g(-1)), in case of filtrate protein, the highest content was attained in medium 16 (2127.4 mg ml(-1)). The best medium for total reducing sugars (TRS) in A. terreus biomass was 9 (33.6 mg g(-1)), the highest direct reducing sugars (DRS) detected in medium 18 (7.3 mg g(-1)) and non-reducing sugar (NRS) reached the highest in medium 9 (29.6 mg g(-1)). In culture filtrates, the medium 9 was the best for TRS (513.2 mg ml(-1)), medium 7 (363.0 mg ml(-1)) for DRS and medium 12 (266.6 mg ml(-1)) for NRS.