Date of Award

Spring 4-9-2020

Semester of Degree

May

Document Type

Open Access Dissertation

Degree Name

Ph.D. in Paper and Bioprocess Engineering

Department

Paper & Bioprocess Engineering

Major Professor

Bandaru V Ramarao

Steering Committee Member

Deepak Kumar

Steering Committee Member

Rengasamy Kasinathan

Steering Committee Member

Thomas Amidon

Steering Committee Member

Shijie Liu

Abstract

Enhancement of hydrolysis yield is achieved by minimizing product inhibition using a membrane bioreactor. A membrane bioreactor was able to mitigate the negative effects of calcium ions on hydrolysis of waste fines and fiber rejects. Enzyme loading and membrane molecular weight cutoff (MWCO) influenced the performance of hydrolysis. At an enzyme loading below 7.5 FPU/ g substrate, a membrane bioreactor didn’t improve the hydrolysis. Better hydrolysis performance is achieved using a membrane with lower MWCO. However, at higher enzyme loadings, membrane MWCO didn’t influence the hydrolysis performance in MBR.

Enzyme in the liquid phase of the hydrolysate was efficiently recovered using zeolite. Enzyme adsorption on zeolite was driven mostly by hydrophobic interactions. Polyethylene glycol (PEG) was very effective at eluting the adsorbed enzyme. A very low concentration of high molecular weight PEG was enough to elute the proteins. The recovered enzyme retained its activity. The adsorption and desorption processes of the enzymes on zeolite β using PEG as an eluent was evaluated using mathematical modeling.

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