Enzymatic hydrolysis of steam-pretreated lignocellulosic materials with Trichoderma atroviride enzymes produced in-house

نویسندگان

  • Krisztina Kovacs
  • Stefano Macrelli
  • George Szakacs
  • Guido Zacchi
چکیده

BACKGROUND Improvement of the process of cellulase production and development of more efficient lignocellulose-degrading enzymes are necessary in order to reduce the cost of enzymes required in the biomass-to-bioethanol process. RESULTS Lignocellulolytic enzyme complexes were produced by the mutant Trichoderma atroviride TUB F-1663 on three different steam-pretreated lignocellulosic substrates, namely spruce, wheat straw and sugarcane bagasse. Filter paper activities of the enzymes produced on the three materials were very similar, while beta-glucosidase and hemicellulase activities were more dependent on the nature of the substrate. Hydrolysis of the enzyme preparations investigated produced similar glucose yields. However, the enzymes produced in-house proved to degrade the xylan and the xylose oligomers less efficiently than a commercial mixture of cellulase and beta-glucosidase. Furthermore, accumulation of xylose oligomers was observed when the TUB F-1663 supernatants were applied to xylan-containing substrates, probably due to the low beta-xylosidase activity of the enzymes. The efficiency of the enzymes produced in-house was enhanced by supplementation with extra commercial beta-glucosidase and beta-xylosidase. When the hydrolytic capacities of various mixtures of a commercial cellulase and a T. atroviride supernatant produced in the lab were investigated at the same enzyme loading, the glucose yield appeared to be correlated with the beta-glucosidase activity, while the xylose yield seemed to be correlated with the beta-xylosidase level in the mixtures. CONCLUSION Enzyme supernatants produced by the mutant T. atroviride TUB F-1663 on various pretreated lignocellulosic substrates have good filter paper activity values combined with high levels of beta-glucosidase activities, leading to cellulose conversion in the enzymatic hydrolysis that is as efficient as with a commercial cellulase mixture. On the other hand, in order to achieve good xylan conversion, the supernatants produced by the mutant have to be supplemented with additional beta-xylosidase activity.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Kinetic Modeling of Enzymatic Hydrolysis of Pretreated Sorghum Bicolor and Rice Husk

In this study, the hydrolysis of pretreated sorghum stem and rice husk was investigated at various initial enzyme concentrations and substrate loadings. The slowdown in enzymatic hydrolysis of lignocellulosic materials with conversion has often been attributed to decreasing the activity of enzyme. A kinetic model was developed and expressed mathematically based on enzyme deactivation for enzyma...

متن کامل

Enzymes for improved hydrolysis of lignocellulosics Doctoral dissertation

The considerably low β-glucosidase activity : FPA ratio of 0.5-0.6 represented by the enzyme complex of Trichoderma reesei RUT C30 results in poor hydrolysis potential. To overcome this problem culture conditions were developed to enhance β-glucosidase production. Mandels’ medium supplemented with tris-maleate buffer proved to be efficient for cellulase production with elevated β-glucosidase ac...

متن کامل

The role of acetyl xylan esterase in the solubilization of xylan and enzymatic hydrolysis of wheat straw and giant reed

BACKGROUND Due to the complexity of lignocellulosic materials, a complete enzymatic hydrolysis into fermentable sugars requires a variety of cellulolytic and xylanolytic enzymes. Addition of xylanases has been shown to significantly improve the performance of cellulases and to increase cellulose hydrolysis by solubilizing xylans in lignocellulosic materials. The goal of this work was to investi...

متن کامل

The enhancement of enzymatic hydrolysis of lignocellulosic substrates by the addition of accessory enzymes such as xylanase: is it an additive or synergistic effect?

BACKGROUND We and other workers have shown that accessory enzymes, such as β-glucosidase, xylanase, and cellulase cofactors, such as GH61, can considerably enhance the hydrolysis effectiveness of cellulase cocktails when added to pretreated lignocellulosic substrates. It is generally acknowledged that, among the several factors that hamper our current ability to attain efficient lignocellulosic...

متن کامل

Role of lignin in the enzymatic hydrolysis of lignocellulose

Characterization, understanding and overcoming barriers of enzymatic hydrolysis of different raw materials is essential for the development of economically competitive processes based on enzymatic treatments. This work focused on factors relevant for the improvement of enzymatic hydrolysis of lignocellulose raw materials derived from softwood. The major interest of the work was in lignin. Speci...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Biotechnology for Biofuels

دوره 2  شماره 

صفحات  -

تاریخ انتشار 2009