Graduate Studies, UNL

 

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

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First Advisor

Ozan Ciftci

Second Advisor

Mark Wilkins

Degree Name

Doctor of Philosophy (Ph.D.)

Committee Members

Chris Proctor, Shudipto Dishari

Department

Engineering

Date of this Version

4-27-2026

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree Doctor of Philosophy

Major: Engineering

Under the supervision of Professors Ozan Ciftci and Mark Wilkins

Lincoln, Nebraska, May 2026

Comments

Copyright 2026, Muhammad Ehtasham Akram. Used by permission

Abstract

This dissertation explores the optimization of chicken feathers keratin hydrolysate (CFKH) production using alkaline hydrolysis (AH) and sub-critical water hydrolysis (SCWH), focusing on acquiring high keratin yield in the hydrolysate. Then, CFKH along with other locally sourced materials, was used to develop bioplastics with regenerative agriculture properties (BioWRAP), with the ultimate objective of applying it as a soil mulch to suppress weeds in agricultural crops. This work also addresses challenges in process design and industrial scale-up of BioWRAP. Chapter 1 is a literature review that introduces terms like biobased, biodegradable, and bioplastics, materials and methods used to make bioplastics, and effects of materials and methods used on mechanical, barrier and other properties. Chapter 2 investigates CFKH production process optimization using AH and SCWH from chicken feathers (CF) and chicken feather meal (CFM). Response surface methodology (RSM) identified optimal conditions. Optimized SCWH achieved 93% keratin recovery (188°C, 120 min, 1:30), compared to 98% recovery for AH (65°C, 24 h, 1 : 8). Chapter 3 focuses on optimizing formulations for BioWRAP using CFKH and other locally sourced biobased materials to optimize film forming and mechanical properties. It highlights the finding that optimized biobased sprayable mulch (BSM) exhibited the highest tensile strength (23 kPa), with an elongation at break of 15.39% and a Young’s modulus of 230 kPa. Chapter 4 extends the work of film-forming solution optimization using corn starch with varying amylose contents (0%, 25%, 55%, and 72%) and glycerol loading (25%, 50%, and 100% w/w of corn starch) on the properties of BSM films. Films were prepared through casting, and results showed a shear-thinning viscosity behavior, with lower initial viscosities at lower amylose contents and moderate glycerol levels. The tensile strength was 0.27 MPa, Young's modulus was 3.23 MPa, and elongation at break was 71.6% in low-amylose and moderate glycerol formulation. Chapter 5 extends the research from lab scale to industrial scale, integrating technoeconomic analysis (TEA) and sensitivity analysis for the BioWRAP production process. Using SuperPro Designer for process simulation, a mass balance confirms that a facility processing 945 MT/year of CFW can produce 30,000 MT/year of BSM. The TEA, conducted via SuperPro Designer, estimates a total capital investment (TCI) of $90.87 million, a net present value (NPV) of $107.93 million and payback time of is 3.21 years at current yields, indicating good feasibility. Sensitivity analysis was performed on the plant's production capacity and the selling price of BSM. An annual capacity of 30,000 MT and a selling price of $2.5/kg were identified as the optimal parameters for the process. This dissertation provides a framework for valorization of chicken feather waste from extraction to application of keratin-based BSM, balancing economic and environmental goals.

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