Development and analysis of a sustainable technology in manufacturing acetic acid and whey protein from waste cheese whey

A multi-stage membrane-integrated hybrid reactor system was developed and investigated for fermentative production of high purity acetic acid and whey protein from waste cheese whey. Integration of largely fouling-free membrane modules with traditional fermenter allowed fermentation with product withdrawal in a continuous scheme. Provision for recycling microbial cells, unconverted sugars and nutrients through cross flow membrane modules resulted in high yield (>98%) and productivity (96 g L−1 h−1) under high cell density. The final forward osmosis stage concentrated dilute acetic acid to 962 g L−1. The environmentally friendly modular design of the membrane integrated system ensured continuous production of more than 98% pure acetic acid in a very simple, compact and flexible plant configuration reflecting all the major characteristics of high process intensification essential to sustainable production and business. Concentrated whey protein (955 g L−1) recovered as a by-product added to the economy of the process raising the possibility of enhanced profit margin. The developed new design fulfills the major expectations of a sustainable technology in terms of benefits to the planet, people and profit. The sustainability parameters in terms of cost of equipment, and production, reduced consumption of material and energy, flexibility, profitability and environmental friendliness have been analyzed in the paper.