Production of enzyme extracts from local strain of ligninolytic bacteria and used to improve the nutritive value of roughages for ruminant feeding
S. A. Hassan, M. T. S. Al-Khateeb
This the first study in Iraq to extract local ligninolytic crude enzyme from local isolate thermophilic filamentous bacteria then use it to decline lignin content and improve dry matter digestibility of low quality roughages. isolation and characterization of ligninolytic degrading microorganisms from different Iraqi ruminant animal decay dung( Camel ,buffalo, cow ,sheep, Lama camel,Deer,horses) .Fifteen from fifty strain showed the ability to grow on Medium contain (Tanic acid).Eight of them showed good growth and were chosen to test their ability to oxidize and hydrolyze lignin extract from petiole base (date palm leaves)to vanillin . Results show that strain NO.1.(Isolated from Iraqi camel decay dung) the best extraction of 42.2mg/ml vanillin from lignin and this was found to be significant ( P≤ 0.01), other isolated strains yielded low amount. The wild strains were characterized using gram staining and acid-fast staining. The strain that had degraded ability was tested. It was gram positive bacteria white and gray color colony, white aerial mycelium, non-diffusible pigments, slow colony Growth and powdery, based on the morphological, biochemical, physiological and cultural characteristics. The wild strain of filamentous bacteria that isolated similarity to strains of the genus. Streptomyces.it was identified as Streptomyces MS .The optimum pH found was 7.0 while the optimum temperature examined was 40°C gave the maximum enzyme activity. Different types of technical lignins were used to detect ability to produce extracellular lignin peroxidase, Moreover, it was observed that, strain collection has also the ability to simultaneously produce enzymes. The obtained results are important for future applications of Streptomyces phenol oxidases in different areas. In batch 6 days degradation experiments this strain utilized lignin as a sole carbon source and achieved maximum lignin degradation on the sixth day. The clear supernatant after five day roughages fermentation was used as ligninolytic local crude enzyme extract called (HAMU) kept in -200C until further in vitro fermentation. Roughages wheat straw (WS),corncobs(Cc),alfalfa hay (AH) were used, treated with HAMU 8%. Highest reduction (p<0.01) in lignin content was observed with treated Cc prior of use for 24 hour 1.899%, the lowest reduction was observed with AH 0.49% . Moreover, The results shown higher (IVDMD%)for most of roughages (WS, Cc, AH).the greatest (p<0.01) improvement in (IVDMD%) was observed with treated Cc 1.984% and the lowest with AH 10.07% in lignin content was shown in Cc treated In vitro fermentation of all pre-treatment roughages increased the IVDMD%. but no signiﬁcantly differences were observed between treatments of Streptomyces MS and HAMU ,These results support the potential application of this organism or its enzymes in ruminants nutrition.