Technical Communication Hydrogen production by Chlamydomonas reinhardtii in a two-stage process with and without illumination at alkaline pH Muhammad Saleem a , Mohammed Harun Chakrabarti b, *, Abdul Aziz Abdul Raman b , Diya’uddeen Basheer Hasan b , Wan Mohd Ashri Wan Daud b , Atif Mustafa c a Jubail University College, Jubail Industrial City, Saudi Arabia b Department of Chemical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia c Department of Environmental Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan article info Article history: Received 18 August 2011 Received in revised form 16 December 2011 Accepted 19 December 2011 Available online 9 January 2012 Keywords: Photosynthesis Biological hydrogen production Chlamydomonas reinhardtii Microalgae abstract This work presents the results of a two-stage (carbon fixation and hydrogen production) experimental study for hydrogen production from microalgae using optical fiber as an internal light source. Effect of absence and presence of light on Chlamydomonas reinhardtii culture’s pH shift is also evaluated. The culture pH value is a function of light intensity; the pH in the alkaline range changes from 7.5 to 9.5 in the presence and absence of optical fiber respectively. The maximum rate of hydrogen production in the presence of exogenic glucose and optical fiber is 6 mL/L cult /hour, which is higher than other reported values. This study has also revealed that the presence of light reduces the lag time for hydrogen production from 12 to 5 h. Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction Hydrogen is believed to be an ideal fuel for the future which does not contribute to greenhouse gas emissions [1]. Hydrogen can be used to produce electricity and contribute to power generation and future transportation. Hydrogen may be produced via pyrolysis, steam reforming and biological processes [2e4]. Among all these methods, the latter has attracted considerable attention due to its high energy production capacity in an economic and green manner [5,6]. The best producer of hydrogen is eukaryotes algae which contain the enzyme hydrogenase. The enzyme produces hydrogen as a waste product during metabolism. The goal of researchers working with algae is to take part of the enzyme which produces hydrogen and insert it into the plant’s photosynthesis framework, thereby coaxing the algae to produce significant amounts of hydrogen by-product [7]. Hydrogenase occurs as a transient (which may last from several seconds to a few minutes) because, in addition to electrons and protons, the light-dependent oxidation of water entails the release of molecular oxygen. Oxygen is a key inhibitor to hydrogen production [8]. Current technological developments in this field have not yet succeeded in over- coming this mutually exclusive nature of the O 2 and H 2 photo- production reactions [5]. Once the technique is developed, algae can provide immediate advantages over other biofuels. Algae can be grown nearly anywhere without the need for large areas of * Corresponding author. Tel.: þ60 37967 7655; fax: þ60 37967 5319. E-mail address: mohammedharun77@yahoo.com (M.H. Chakrabarti). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 37 (2012) 4930 e4934 0360-3199/$ e see front matter Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2011.12.115