In this study an attempt was made to optimize the cultural and nutritional conditions for xylanase production by Bacillus species in submerge fermentation process. Whole fermentation process was carried out in 250 ml Erlenmeyer flask with agitation speed of 140 rpm. Bacillus subtilis exhibit maximum xylanase production at initial medium pH of 8, substrate concentration of 2% with inoculum size of 2% at 35 C for 48 h of fermentation period. Further supplementation of sucrose, (NH 4) 2 SO 4 and peptone as a carbon and nitrogen sources favored enzyme production. The other strain Bacillus megaterium showed its peak xylanase production at initial medium pH of 8, inoculum size of 1.5% with substrate concentration of 1.5% at incubation temperature of 40 C for 72 h of fermentation period. The best carbon and nitrogen sources are xylose, KNO 3 and malt extract. Both strains can also utilize molasses at 0.5% concentration for xylanase production can grow in medium containing 0.2% NaCl (B. subtilis BS04) and 0.8% NaCl (B. megaterium BM07) respectively. The optimum temperature of xylanase was 50 C and pH was 5 and 5.5 by B. subtilis BS04 and B. megaterium BM07 respectively.

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This study was conducted to analyse structural changes through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) after alkaline pretreatment of wheat straw for optimum steaming period. During the study, 2 mm size of substrate was soaked in 2.5% NaOH for 1 h at room temperature and then autoclaved at 121°C for various steaming time (30, 60, 90 and 120 min). Results revealed that residence time of 90 min at 121°C has strong effect on substrate, achieving a maximum cellulose content of 83%, delignification of 81% and hemicellulose content of 10.5%. Further SEM and FTIR spectroscopy confirmed structural modification caused by alkaline pretreatment in substrate. Maximum saccharification yield of 52.93% was achieved with 0.5% enzyme concentration using 2.5% substrate concentration for 8 h of incubation at 50°C. This result indicates that the above-mentioned pretreatment conditions create accessible areas for enzymatic hydrolysis.

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Ö Z E TBu çalışmada, substrat olarak şeker kamışı kullanılarak batık kültür fermentasyonuyla Trichoderma harzianum'dan endoglukanaz üretildi. Enzim üretimini iyileştirmek için belirli bir zaman aralığında çeşitli parametreler optimize edildi. Ortamın başlangıç pH'ı 4.0, aşılama miktarı %2, şeker kamışı küspesi derişimi %2 ve inkübasyon sıcaklığı 30°C de ve 72 saatlik fermentasyon süresiyle optimum enzim verimi elde edildi. Fermentasyon ortamına tween-80 (%0.2) ilavesi endoglukanaz üretimini ciddi miktarda etkilemektedir. Buna ilave olarak sentetik karbon ve azot kaynağı olarak sırasıyla NaNO 3 ve glikoz desteği, enzim üretimine katkı vermiştir. Çalışmanın sonuçları büyük ölçekli enzim üretimi için çok yararlıdır. Anahtar KelimelerEndoglukanaz; T. harzianum; küspe; batık kültür fermentasyonu. A B S T R A C TI n this study, endoglucanase was produced from Trichoderma harzianum in submerged fermentation using sugarcane as a substrate. For enhanced enzyme production, various parameters were optimized by one factor at a time approach. Maximum enzyme yield was obtained with initial medium pH of 4.0, inoculum size of 2%, sugarcane bagasse concentration of 2% and incubation temperature of 30 o C for 72 h of fermentation period. Addition of tween-80 (0.2%) to the fermentation medium had significant impact on endoglucanase production. Further supplementation of glucose and NaNO 3 as synthetic carbon and nitrogen source favoured enzyme production respectively. Results of this study are very helpful in large scale enzyme production.