Engineering a Biomanufacturing Process Converting Whey into Biodegradable Plastics in Dairy Cooperative Supply Chain

Thesis Abstract

The study investigates a biomanufacturing process that converts dairy whey into biodegradable plastics within a integrated dairy cooperative supply chain, addressing environmental pollution from whey disposal and value loss from underutilized by-products. The aim is to design, optimize, and validate a scalable enzymatic or microbial fermentation route that yields polyhydroxyalkanoate (PHA) precursors and final bioplastic with commercially viable properties, while aligning with cooperative governance and logistics. Specific objectives include (1) characterizing whey composition across five processing plants and identifying key carbon sources for biopolymer synthesis; (2) developing a techno-economic and life cycle assessment (LCA) framework to evaluate sustainability and profitability; (3) engineering a biomanufacturing workflow—comprising substrate pretreatment, fermentation or enzymatic conversion, and downstream processing—to maximize PHA yield and material properties; (4) validating process performance at pilot scale (1000 L), and (5) assessing organizational readiness, risk, and adoption barriers within the dairy cooperative network. The methodology adopts a mixed-methods design grounded in systems thinking and innovation diffusion theory. The population includes three dairy cooperatives, two whey processing facilities, and associated supply-chain partners. A stratified sampling approach yields 30 whey samples representing seasonal variation and two pilot plants. Data collection combines chemical analyses (HPLC for monomer composition, GC-MS for by-products, and NIR spectroscopy for real-time composition), rheological measurements, and material characterization (DSC, TGA, FTIR, and GPC for molecular weight distribution). Process data are gathered from 12 fermentation runs across varying feedstock ratios and inoculum conditions. Qualitative insights are obtained from 24 semi-structured interviews with plant managers, process engineers, and cooperative board members, analyzed via thematic analysis, and triangulated with quantitative outputs. Validation of instruments employs content validity by subject-matter experts and reliability testing using Cronbach’s alpha for survey items (>0.80 acceptable). Data analysis integrates regression and ANOVA to identify significant factors affecting yield and material properties, response surface methodology for optimization, and a life cycle assessment to quantify environmental impacts (global warming potential, eutrophication, and energy use). A discounted cash flow model plus sensitivity analyses assesses economic feasibility, while a systems dynamics model evaluates flow of whey through the cooperative network under different governance scenarios. Expected findings indicate a viable biomanufacturing route with PHA-rich fractions achieving material properties (tensile strength 25–35 MPa, elongation at break 50–120%) comparable to certain conventional bioplastics, and a break-even point within 3–5 years under cooperative-scale production. The process is anticipated to reduce whey disposal costs by 60–75% and lower net lifecycle greenhouse gas emissions by 25–40% relative to conventional waste management. The integration within a cooperative supply chain is projected to strengthen member engagement, reduce logistics waste, and create a new revenue stream. Sensitivity analyses are likely to reveal critical factors including substrate purity, inoculum performance, energy intensity of downstream processing, and market price volatility for bioplastics. Contribution to knowledge encompasses (i) a demonstrable, scalable model for converting dairy by-products into high-value biopolymers within a real-world supply chain, (ii) an integrated framework combining techno-economic analysis, LCA, and organizational readiness to assess circular bioeconomy initiatives in agriculture-based cooperatives, and (iii) empirical evidence on process–organization alignment that informs policy and investment decisions for sustainable dairy industries. The study concludes that a carefully staged pilot-to-commercial transition within a dairy cooperative context can deliver environmentally beneficial outcomes while enhancing economic resilience. Recommendations include policy support for cooperative financing, investment in modular biomanufacturing units, development of standardized whey feedstocks, and ongoing monitoring of environmental and social metrics to sustain long-term value creation.