Journal of Bioprocessing & Biotechniques

Statistical Optimization of Parameters Affecting Polyhydroxybutyrate(PHB) Recovery by Dispersion Method from Alcaligenes Cells and Its Characterization

Abstract

Abhishek Dutt Tripathi and Suresh Kumar Srivastava

In the present study, efforts have been made to optimize the three process variables i.e., incubation time, temperature of separation and hypochlorite concentration for enhanced polyhydroxybutyrate (PHB) recovery from Alcaligenes cells which may serve as precursor for bio-plastic production. Screening of bio-plastic (PHB) producing microorganism was done by TEM (Transmission electron microscopy). Initially, three recovery methods were applied to achieve efficient PHB recovery which included; Alkali treatment, ATPS (Aquas two phase separation (PEG 6000)/ KH₂PO₄) and chloroform-hypochlorite dispersion (1:1, v/v). Maximum PHB recovery of 95 ± 0.5% with 97.0 ± 0.29% purity was obtained by dispersion method. In order to enhance the PHB recovery further, dispersion process was optimized using design expert (DX 8.0.6) software. PHB recovered under optimized physical condition comprising: incubation temperature 37°C, incubation time 28 h and hypochlorite concentration of 30.0, gave maximum PHB recovery of 98.2 ± 0.05% against the predicted yield of 99.0 ± 0.05% with 99.0% purity. Characterization of recovered polymer as PHB was done by FTIR (Fourier transform infrared microscopy) and NMR (Nuclear magnetic resonance spectroscopy).