Valorization of Egg Shell Biowaste and Brewery Wastewater for the Enhanced Production of Fumaric Acid

Abstract

Two different industrial wastes, namely egg shells and brewery wastewater were valorized for the enhanced production of FA by adopting immobilization strategy. Egg shells were used both as a source of CaCO3 and as immobilizing support, while brewery wastewater was used as fermentation medium for fumaric acid production through submerged fermentation. To check the suitability as fermentation medium, compositional analysis of brewery wastewater was carried out. The filamentous fungus, Rhizopus oryzae 1526 was immobilized on egg shell surfaces that developed into thin (ca. 1 mm) biofilms. Biofilms were used for fumaric acid production at the optimized fermentation parameters (25 g L−1 total solids concentration of brewery wastewater, 30 °C and 150 rpm). Immobilized mycelia were also experimented with glucose salt medium for enhanced fumaric acid production. For biofilm formation, different parameters viz. number of egg shell for immobilization (three), spore concentration (1.0 × 106 per mL), incubation time (24 h) and flask shaking speed (150 rpm) were optimized. As compared to free-cell, biofilms mediated submerged fermentation markedly enhanced the production and volumetric productivity of fumaric acid from 30.23 ± 1.23 to 47.22 ± 0.77 g L−1 (i.e. by 56 %) and 0.419 to 1.657 g L−1 h−1 (i.e. by 3.95 times), respectively. The application of egg shells with dual functions (source of CaCO3 and immobilization device) for fumaric acid production was a new approach of valorization with economic and ecological benefits.