Effects of AFEX on Activity of Cellulase
نویسندگان
چکیده
A critical parameter affecting the economic feasibility of lignocellulosic bioconversion is the production of inexpensive and highly active cellulase enzymes in bulk quantity. A promising approach to reduce enzyme costs is to genetically transform plants with the genes of these enzymes, thereby producing the desired cellulases in the plants themselves. Extraction and recovery of active proteins or release of active cellulase from the plants during bioconversion could have a significant positive impact on overall lignocellulose conversion economics. The effects of ammonia fiber explosion (AFEX) pretreatment variables (treatment temperature, moisture content, and ammonia loading) on the activity of plant-produced heterologous cellulase enzyme were individually investigated via heat treatment or ammonia treatment. Finally, we studied the effects of all these variables in concert through the AFEX process. The plant materials included transgenic tobacco plants expressing E1 (endoglucanase from Acidothermus cellulolyticus). The E1 activity was measured in untreated and AFEX-treated tobacco leaves to investigate the effects of the treatment on the activity of this enzyme. The maximum observed activity retention in AFEX-treated transgenic tobacco samples compared with untreated samples was approx 35% (at 60°C, 0.5:1 ammonia loading, and 40% moisture). Based on these findings, it is our opinion that AFEX pretreatment is not a suitable option for releasing cellulase enzyme from transgenic plants. 1184 Teymouri et al. Applied Biochemistry and Biotechnology Vol. 113–116, 2004 Index Entries: Ammonia fiber explosion; endoglucanase; Acidothermus cellulolyticus; transgenic tobacco; E1cd.
منابع مشابه
Biotechnology for Biofuels
Background: Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising pretreatments using alkaline and acidic pH that have distinctive differences in pretreatment chemistries. Results: Comparative evaluation on these two pretreatments reveal that (i) AFEX-pretreate...
متن کاملThe impacts of pretreatment on the fermentability of pretreated lignocellulosic biomass: a comparative evaluation between ammonia fiber expansion and dilute acid pretreatment
BACKGROUND Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising pretreatments using alkaline and acidic pH that have distinctive differences in pretreatment chemistries. RESULTS Comparative evaluation on these two pretreatments reveal that (i) AFEX-pretreate...
متن کاملCellulase adsorption and relationship to features of corn stover solids produced by leading pretreatments.
Although essential to enzymatic hydrolysis of cellulosic biomass to sugars for fermentation to ethanol or other products, enzyme adsorption and its relationship to substrate features has received limited attention, and little data and insight have been developed on cellulase adsorption for promising pretreatment options, with almost no data available to facilitate comparisons. Therefore, adsorp...
متن کاملAccess of cellulase to cellulose and lignin for poplar solids produced by leading pretreatment technologies.
Adsorption of cellulase on solids resulting from pretreatment of poplar wood by ammonia fiber expansion (AFEX), ammonia recycled percolation (ARP), controlled pH, dilute acid (DA), flowthrough (FT), lime, and sulfur dioxide (SO(2)) and pure Avicel glucan was measured at 4 degrees C, as were adsorption and desorption of cellulase and adsorption of beta-glucosidase for lignin left after enzymatic...
متن کاملInhibition of Trichoderma Species from Growth and Zoospore Production of Phytophthora Drechsleri and Their Effects on Hydrolytic Enzymes
Understanding the function of Trichoderma species in the control of Phytophthora drechsleri in pistachio orchards is very important. In this study, the effects of liquid extra-cellular secretions and volatile compounds secreted by 27 isolates of Trichoderma harzianum, T. crassum, T. koningii, T.aureoviride, T. asperellum, T. brevicompactum, T.longibrachiatum and T. virens were investigated on ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2004