Title: Bioconversion of restaurant waste into Polyhydroxybutyrate (PHB) by recombinant E. coli through anaerobic digestion

Authors: Majd Khalid Eshtaya; Nor 'Aini Abdul Rahman; Mohd Ali Hassan

Addresses: Faculty of Biotechnology and Biomolecular Sciences, Department of Bioprocess Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia ' Faculty of Biotechnology and Biomolecular Sciences, Department of Bioprocess Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia ' Faculty of Biotechnology and Biomolecular Sciences, Department of Bioprocess Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

Abstract: The effect of temperature (30°C, 37°C, uncontrolled) and initial pH adjustment at pH 7 in the anaerobic digestion process was investigated to enhance the production of organic acids from restaurant waste. The highest organic acid level obtained was 39.6 g/L on the fifth day of fermentation conducted at 30°C and initial pH 7. The acids produced corresponded to 39.4% of the yield based on the initial concentration of substrate. The main organic acids produced were lactic and acetic acids. Using organic acids from fermented restaurant waste, recombinant Escherichia coli pnDTM2 gave PHB concentration, PHB content and PHB productivity of 9.2 g/L, 44% w/w and 0.54 g/L/h, respectively, in a pH stat fed-batch culture.

Keywords: organic acids; anaerobic digestion; restaurant waste; polyhydroxybutyrate; bioconversion; PHB; recombinant E. coli; lactic acid; acetic acid; Escherichia coli; waste management.

DOI: 10.1504/IJEWM.2013.050521

International Journal of Environment and Waste Management, 2013 Vol.11 No.1, pp.27 - 37

Accepted: 29 Jan 2011
Published online: 20 Sep 2014 *

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