Biohydrogen Production Using Dark and Photo Fermentation: A Mini Review Noor Safwan Muhamad 1 , Nor Asiah Johan 2 , Mohamed Hasnain Isa 3 , Shamsul Rahman M Kutty 4 , 1,2,3,4 Department of Civil Engineering, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak, MALAYSIA. asiahjohan@gmail.com ( 2 corresponding author) Abstract—Biological production of hydrogen is the most environmental friendly method in producing hydrogen, a clean fuel which produces only water upon combustion. There are many references available on biohydrogen production. This paper presents a review on current biological hydrogen production focusing on dark and photo fermentation processes. Limitation for hydrogen production such as source of substrate, type of microorganism employed and operational parameter are discussed in this paper. Keywords- Biohydrogen; energy; dark fermentation; photo fermentation. I. INTRODUCTION Extensive use of fossil fuel as the source of energy leads to energy crisis due to the depletion of fuel which is a nonrenewable source of energy. The emission of greenhouse gases also creates environmental problems such as global warming and acid rain which has become more alarming these days. Kazim [1] reported that UAE as one of the major oil exporters would fail to meet its share in the oil and natural gas market demand by the year 2015 and 2042, respectively. An econometric study in Malaysia shows that it will become a net oil importing country in 2013 while the carbon emission will triple by the year 2030 due to the increasing demand of energy [2]. In response to these problems, searches for alternative energy sources have intensified; the priority will go to the one which is clean and renewable. Hydrogen can be considered as one of the promising alternatives to fossil fuel since it only produces water during combustion and has high energy content (122 kJ/g) compared to the fossil fuels such as petroleum (44 kJ/g), gas (52 kJ/g), coal (40 kJ/g), methane (50.1 kJ/g) and ethanol (26.5 kJ/g). Currently, 40% hydrogen is produced from natural gases, 30% from heavy oil and naphtha, 18% from coal, 4% from electrolysis and about 1% from biomass [3]. The need for hydrogen energy is rapidly increasing and will become crucial as over 50M tonnes of hydrogen are currently traded per annum and the demand is increasing about 10% per year [4]. A number of hydrogen production processes have been developed and applied such as steam reforming and catalytic decomposition of natural gas, partial oxidation of heavy oils, coal gasification and steam- iron coal gasification. On the other hand, thermo-chemical, photochemical, photo-electro-chemical and photo-biological processes are still at the research and development stage [5]. Most of the current hydrogen producing practices are energy intensive, costly and still require the use of fossil fuel which undermine the objective of having hydrogen as an alternative source of energy. Biological production of hydrogen which utilizes waste products as substrate has been extensively studied to overcome these problems. Unfortunately, the production rate and yield of biohydrogen using this technique is still too low for commercial application. Biological hydrogen production has many advantages compared to other hydrogen production techniques. For example, the energy produced by converting biohydrogen using fuel cells would have twice the efficiency of burning biofuel in an internal combustion engine, near zero levels of air pollution as compared to other biofuel and also the possibility of capturing the carbon dioxide released during fermentation which reduces the carbon emission to the environment [6]. There are several methods for hydrogen production through biological processes; a) biophotolysis or process of splitting water using algae (direct biophotolysis) and cyanobacteria (indirect biophotolysis) in presence of light energy, b) photodecomposition or photo fermentation of organic compounds using photo fermentative bacteria, c) dark fermentation using dark fermentative bacteria, d) bioelectrohydrogenesis or a process which apply low voltage current to generate microbial fuel cell to produce hydrogen from organic waste or fatty acids [6,7,8]. Basically, these processes can be divided into two major categories which are light dependent and light independent processes as shown in Figure 1 [9]. 978-1-4577-1884-7/11/$26.00 ©2011 IEEE Authorized licensed use limited to: UNIVERSITI TEKNOLOGI MARA. Downloaded on June 23,2020 at 03:25:04 UTC from IEEE Xplore. Restrictions apply.