📋 Case Study

Food-Grade Citric Acid Fermentation Upgrade — Cargill Decatur

High steam demand for sterilization and evaporation; mycelial waste sent to landfill; citrate recovery <72% due to precipitation inefficiencies

🏗️ Project Overview

Modernization of Aspergillus niger fermentation and downstream processing

🎯 Challenge

High steam demand for sterilization and evaporation; mycelial waste sent to landfill; citrate recovery <72% due to precipitation inefficiencies

🔧 Design Approach

Installed solar thermal preheating + mechanical vapor recompression (MVR); implemented enzymatic cell lysis and ion-exchange resin regeneration with CO₂ stripping

📐 Design Diagram

Sterilization(Steam)Evaporation(Steam)Solar ThermalPreheatingMVR SystemCO₂StrippingEnzymaticLysisIon-ExchangeResinSteam ↓ 62%Citrate recovery ↑ to 89%Protein yield: 68%High steam demandMycelial waste → landfillCitrate recovery <72%

AI-generated project design illustration

📐 Key Calculations

Steam Reduction Ratio

Pre-MVR Steam / Post-MVR Steam
Result: 1.0 → 0.38
Primary energy intensity KPI

Mycelial Waste Valorization Yield

Protein Extract / Dry Biomass × 100
Result: 68%
Converts liability into animal feed co-product revenue

📊 Results

Steam use cut by 62%; mycelial waste diverted 100% to value stream; overall process yield increased to 89%

💡 Lessons Learned

  • MVR payback improves dramatically when paired with low-carbon thermal preheat
  • Resin regeneration with CO₂ avoids NaOH waste and simplifies wastewater treatment

Key Takeaways

  • 1MVR payback improves dramatically when paired with low-carbon thermal preheat
  • 2Resin regeneration with CO₂ avoids NaOH waste and simplifies wastewater treatment