Characterization Of Penicillium Oxalicum That Used Miscanthus And Rice Straws As Inducing Carbon Source To Secrete Cellulases For Distinct Biomass Saccharification

Cellulases are evaluated as the third largest enzyme market over the world.Crop straw residues could not only be convertible for bioethanol production,but are also able to use as carbon source to induce fungal secreting cellulase enzymes for lignocellulose degradation.In the Part I of this study,I selected two pairs of Miscanthus(Msi62,Msa05)and rice(NPB,Osfc16)and commercial avicel cellulose materials as carbon sources to incubate with Penicillium oxalicum 114-2.Using the induced crude enzyme solution,total 20 distinct lignocellulose materials were hydrolyzed,and their released hexoses yields were measured as shown below: Meanwhile,total 24 rice lignocellulose samples were used as carbon source to induce P.oxalicum 114-2 secreting cellulase enzymes.Then two Miscanthus lignocellulose materials were applied as the substrates for enzymatic hydrolysis using the secreted enzymes by P.oxalicum 114-2.Finally,using seven representative rice lignocellulose secreted-cellulase,this study attempted to sort out the mechanism of lignocellulose structure and features impacts on hexoses yields.The major results were described below:1.Under 0.5% Na OH pretreatment,the Osfc16 lignocellulose was almost completely digested with hexoses yield of 100%(% cellulose),whereas the Eucalyptus and Populus materials showed the hexoses yields of 18% and 19% even though under pretreatments with 1% Na OH and 0.8% Tween-80.2.Using Msi62-induced cellulase enzymes and commercial enzyme CTec2,total 20 lignocellulose materials showed their average hexoses yields of 50% and 49% after 0.5% Na OH pretreatment,which were higher than those of other Miscanthus and rice induced enzymes.Under pretreatment with 1% Na OH + 0.8% Tween-80,total 20 lignocellulose materials showed their average hexose yield of 72% released from CTec2 hydrolysis,whereas the average hexoses yield was 58% released from Osfc16-induced cellulases hydrolysis.3.Comparison of average hexoses yields indicated that the induced enzyme activity was ranked as Osfc16 > NPB,Msi62 > Msa05.It also suggested that the Xyl/Ara ratio of alkali-insoluble hemicellulose may be the major factor on hexoses yields of enzymatic hydrolysis of total 20 lignocellulose materials using the P.oxalicum 114-2 secreted cellulases enzymes.4.Among total 24 rice-induced cellulase enzymes,rice H65 sample-induced cellulase had the highest specific activity of 102.70 FPU/m L,whereas the 9311-and H51-induced cellulases showed the average hexoses yields of 47% and 45% under 1% Na OH pretreatment.In addition,the H37-induced enzyme showed the lowest hexoses yield of 31%.5.Correlation analysis indicated that cellulose level of rice materials incubated with P.oxalicum 114-2 was negative factor on the the filter paper activity of secreted cellulases,whereas their hemicellulose content was positive on total protein level of secreted solution.Furthermore,the Xyl/Ara ratio of hemicelluloses was the negative factor on the specific activity of the secreted cellulases.In addition,those factors were also consistent with the hexoses yields released from secreted-cellulase hydrolysis after different chemical pretreatments.