Semester

Spring

Date of Graduation

2001

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Ray Y. K. Yang.

Abstract

This research aims to increase the efficiency of utilizing lignocellulosic materials, which have great potential as future energy and chemical feed stocks, and may finally substitute the diminishing hydrocarbon resources. This work involved two main parts: (a) comparison of efficiency of different pretreatment methods on lignocellulosic materials; and (b) enhancing enzymatic hydrolysis in a continuous tubular membrane reactor (TMR) process.;The alkaline oxidation pretreatment method was found to be more efficient than ammonia steeping pretreatment in lignin removal and digestible cellulose enrichment for the raw substrates chosen for this study, namely, yellow poplar (hardwood) and corn cob (herbaceous crop).;A combination of reactor incline and shaking speed of 46.7°/180 rpm produced continuous and steady transportation of insoluble substrates through the hollow fibers of polymeric TMR, when no cellulolytic enzymes were added, due probably to the homogenous suspension of solid substrate inside the hollow fibers. This is of great importance, since increasing the homogeneity of insoluble substrate in reaction mixture enhanced the enzyme-substrate contact, a factor crucial to higher hydrolysis rate. This combination was applied for all the later continuous enzymatic hydrolysis experiments in TMR.;Both surfactants, Pluronic F68 and Tergitol NP 9, were effective in enhancing the enzymatic hydrolysis of all the substrate investigated in our TMR system. This is proven by the increased steady state substrate conversion, when either surfactant is added. The greatest enhancement in steady state conversion (96.3%) was for ammonia steeping pretreated corn cob, when surfactant Pluronic F68 was added.

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