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Title:	Biohydrogen production from chemically pre-treated palm oil mill effluent (POME) using immobilised thermophilic anaerobic bacteria
Authors:	Shalini Narayanan (P90467)
Supervisor:	Peer Mohamed, Dr.
Keywords:	Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia Palm oil industry Biohydrogen Thermophilic anaerobic bacteria
Issue Date:	10-May-2021
Description:	Palm Oil Mill Effluent (POME) contains high level of organic materials and nutrients which makes it a potential low cost substrate for biological process. Anaerobic treatment system in continuous stirred tank bioreactor (CSTR) often encounter problems with washout of biomass at high dilution rates and tackling the abundant POME has been a great challenge. Hence, an effective handling system is so critical to preserve and maintain anaerobic bacteria in the process. This research aimed to establish immobilisation method of mixed culture anaerobic bacteria to retain bacteria population for biohydrogen gas production. In order to enhance an efficiently high soluble carbohydrate substrate content, POME was subjected to various 1.5% (w/v) chemical pre-treatment, such as sodium hydroxide (NaOH), hydrochloric acid (HCl), sulfuric acid (H2SO4), phosphoric acid (H3PO4) and nitric acid (HNO3). Results has indicated that among different chemical pre-treatment on POME, with using 1.5% H3PO4 would generate maximum biohydrogen production of 0.193 mmol/L/h, which corresponded to a yield of 1.51 mol H2/mol TCconsumed and with initial total soluble carbohydrate concentration of 23.52 g/L was achieved. Amongst diverse concentration of H3PO4, 2.5% H3PO4 has maximum hydrogen production rate, 0.208 mmol/L/h and yield of 1.69 mol H2/mol TCconsumed. POME pre-treated with 2.5% H3PO4 produce biohydrogen that was 2.35-fold higher than untreated POME. Pre-treated POME with suspended anaerobic sludge was then subjected to CSTR that achieved maximum biohydrogen production rate of 8.7 L H2/L POME/d and biohydrogen yield of 2.54 mol H2/mol TCconsumed at optimal HRT of 6 hours. Powdered activated carbon, inert material and inorganic synthetic polymer gel was mixed with 6 hours HRT effluent for cell immobilisation to produce anaerobic bacteria pellet. Batch fermentation using immobilised pellets produce maximum hydrogen production rate, 0.233 mmol/L/h and yield, 1.89 mol H2/mol TCconsumed that corresponds to1.12-fold higher performance than suspended bacteria. Physical characteristic of immobilised pellets analysed via field emission scanning electron microscopy (FESEM) shows majority rod-shaped bacteria existent at internal and external surface of pellet. Anaerobic bacteria community analysed through 16S ribosomal DNA (16S rDNA) subunit, hypervariable regions 3 to 4 (V3-4) gene sequences indicates that preservation of anaerobic bacteria via immobilisation after dry storage (room temperature) for 100 days shows that around 38 different OTU were successfully withheld in activated carbon-synthetic inorganic polymer gel of which 81% were known to be hydrogen-producing bacteria. Predominant phyla present in this anaerobic the system were of Firmicutes, with a total of 98% existence. In Firmicutes phylum, abundancy around 95% was comprised of Clostridia and 4% of Bacilli bacteria classes. The application of synthetic inorganic polymer on immobilising and preserving anaerobic bacteria can be accepted to be a promising biocompatible component.,Master of Science
Pages:	200
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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