CHEMICAL ENGINEERING TRANSACTIONS VOL. 56, 2017 A publication of The Italian Association of Chemical Engineering Online at www.aidic.it/cet Guest Editors: Jiří Jaromír Klemeš, Peng Yen Liew, Wai Shin Ho, Jeng Shiun Lim Copyright © 2017, AIDIC Servizi S.r.l., ISBN 978-88-95608-47-1; ISSN 2283-9216 Growth of Bacillus Coagulans Using Molasses as a Nutrient Source Nur Farzana Ahmad Sanadi a , Yee Van Fan a , Chee Woh Leow a , Jin Hong Wong a , Yin Shin Koay a , Chew Tin Lee a* , Lee Suan Chua b , Mohamad Roji Sarmidi c a Faculty of Chemical and Energy Engineering, Department of Bioprocess Engineering, Universiti Teknologi Malaysia, 81310 Johor b Institue of Bioproduct Development, Universiti Teknologi Malaysia, 81310 Johor c Innovation Centre in Agritechnology for Advanced Bioprocessing (ICA), Universiti Teknologi Malaysia, 81310 Johor ctlee@utm.my Bacillus coagulans (B. coagulans) can be utilized as microbial inoculant to speed up the bioremediation of wastewater. The effectiveness of the microbial inoculant for treatment is highly selective and relying on the characteristics of the wastewater. A feasible carbon source must be first chosen to pre-culture the microbe prior to the bioremediation. Commercial nutrient broths are efficient to grow the microbial; they are costly for the treatment of large volume of wastewater treatment. This study aims to evaluate the growth rate of B. coagulans using a cheaper nutrient source, i.e. molasses. The commercial Man, Rogosa and Sharpe (MRS) media was used as a benchmark. The growth rate of B. coagulans was conducted at different concentrations of molasses (1 %, 3 % and 5 % (w/v)) and in the MRS broth as benchmark. B. coagulans grown in the MRS has shown a much higher maximum specific growth rate (0.69 h -1 ) compared to that grown in 1 % (w/v) molasses (0.14 h -1 ). No growth was observed in the higher concentrations of molasses (3 and 5 % (w/v)). Measuring the colony- forming units of B. coagulans in both the MRS and molasses mediums validated the results. Molasses is a desirable carbon source as it is relatively cheaper and easily available. More studies are needed to improve the maximum specific growth rate of B. coagulans in 1 % (w/v) of molasses. 1. Introduction Bioremediation is a process using microorganism to breakdown the environmental pollutants (Kumar et al., 2011). It is relatively low-cost and environmental-friendly and has received good public acceptance (Mary, 2011). To ensure effective bioremediation, a suitable microorganism must be selected based on its ability to degrade contaminants. Bacillus coagulans was originally introduced as a probiotic bacterium, often marketed wrongly as ‘Lactobacillus sporogenes' (Food info, 2016). B. coagulans has been applied for the bioremediation of wastewater due to its ability to digest contaminants (nitrogen, phosphorus, heavy metals) and to convert it to biomass (Kotay and Das, 2007). B. coagulans has been used for the production of L-lactic acid (Ma et al., 2014), and lactic acid (Kumar et al., 2005). The microbes were cultured in a nutrient medium to a desired quantity before being applied to the wastewater. Several types of carbon sources such as glucose, fructose and lactose were used for the wastewater treatment, but the usage of such pure or mixed media at industrial scale would incur a high cost (Michailides et al., 2015). There is a need to find a more economical carbon source for the industrial application. Molasses is an important agro-industrial by-product that contains high sugar contents (48–50 %) (Quan et al., 2005). Molasses can be used as a cheaper nutrient source for microbial growth. Zhang et al. (2008) used molasses as a carbon source for the remediation of selenium; for the sulphate reducing bacteria (Telcu et al., 2009). Molasses have been used for the production of cellulose (Bae et al., 2005); fermentation of amylolytic enzyme (Najafpour and Shan, 2003); and for the biological removal of Cr(VI) in the wastewater (Michailides et al., 2015). The Malaysian market price of the liquid molasses is around MYR 27/ kg, whereas the common DOI: 10.3303/CET1756086 Please cite this article as: Ahmad Sanadi N.F., Fan Y.V., Leow C.W., Wong J.H., Koay Y.S., Lee C.T., Chua L.S., Sarmidi M.R., 2017, Growth of bacillus coagulans using molasses as a nutrient source, Chemical Engineering Transactions, 56, 511-516 DOI:10.3303/CET1756086 511