انتاج انزيم السيليلز من عزلة محلية لبكتريا B167 Streptomyces sp. واستخدامه في انتاج الوقود الحيوي == Cellulase Production From Local Isolate of Streptomyces Sp.B167 And Its Application In Biofuel Production
Author name:
بنان محمود سليمان
Supervisor name:
ناظم حسن حيدر
General topic:
Biology
Specific topic:
Biotechnologies
Degree:
Master
University:
University of Baghdad - College Of Science - Department Of Biotechnology
Language:
English
University location:
Baghdad
First pages:
24T2901 - p.pdf
Abstract:
هدفت الدراسة الحالية الى انتاج انزيم السليليز من بكتريا الستربتومايسس ودراسة تاثير بعض الظروف الزرعية على انتاج الانزيم; انتاج الوقود الحيوي من المخلفات السليلوزية من خلال التحلل المائي للمخلفات بالاحماض والانزيمات المايكروبية. تم غربلة 74 عزلة لبكتريا St | The current study was aimed to produce biofuel from cellulosic waste material degraded by local isolate Streptomyces. Seventy four isolates of Streptomyces were screened for cellulase production in solid and liquid media. The results showed higher capability of isolate Streptomyces sp. B 167 for cellulase production and bioconversion of cellulose. Therefore, it was selected for further studies. The results of optimization revealed that the cellulase enzyme productivity by the isolate Streptomyces sp. B 167 reached to 2.1 and 2.28 U/ml after 48 h of incubation time and pH 7 respectively. Cellulase productions in tested isolate improved (2.57 U/ml) by supplementation of cellulose liquid medium with 1 % of yeast extract as nitrogen source. Additives of carbon sources like (manitol, glucose, maltose, sucrose and starch) to the process of saccharification did not improve the cellulase productivity. The bioconversion of cellulosic waste to reducing sugar was maximum with Banana peels (77.78 %) followed by the rice husk (75.56 %), orange peels (71.11 %), corn steep peels (60.0 %) and lowest bioconversions (53.33 %) were recorded with sawdust. The degradation of cellulosic waste increased with increasing substrate concentration. Maximum cellulase productivity (3.18 U/ml) and bioconversion (86.1 %) was obtained at 3 % (w/v) of cellulosic waste (Banana peels). Saccharification of cellulosic waste with different treatment methods was studied. The pretreatment of cellulosic waste with 1 % HCl and H2SO4 produces 21 and 15.8 g of reducing sugar / 100 g of cellulosic waste. In comparison, hydrolysis with Streptomyces sp. B 167 enzymes resulted a significantly higher amount of reducing sugar yield (25 g / 100 g cellulosic waste). Further fermentation of cellulosic hydrolysates was performed using Saccharomyces cerevisiae using stationary fermentation condition. Maximum yield of ethanol were (0.30, 0.19 and 0.10 g ethanol / g glucose) observed with Streptomyces sp. B 167 enzymes, HCl and H2SO4 hydrolysates respectively after 48 h of fermentation
