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Effects of physicochemical parameters on the production of phenolic acids from palm oil mill efﬂuent under liquid-state fermentation by Aspergillus niger IBS-103ZA
Parveen Jamal ⇑, Zulkarnain Mohamed Idris, Md Zahangir Alam
BioenvironmentalEngineering Research Unit (BERU), Department of Biotechnology Engineering, Faculty of Engineering, International Islamic University Malaysia, 50728 Gombak, Kuala Lumpur, Malaysia
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The present investigation is an effort to develop an environmentally friendly and cost-effective liquidstate fermentation process by introducing a new locally isolated fungalstrain of Aspergillus niger (IBS103ZA) for the production of phenolics from a new source, palm oil mill efﬂuent (POME). Sucrose, manganese sulphate (MnSO4) and temperature were identiﬁed as the most signiﬁcant variables in improving phenolics production. Optimisation increased the total phenolic content from 856 ± 2.22 to 941 ± 3.72 GAE mg/l at 35.0 °C, 6.0% (w/v) sucrose, 2.7% (w/v) MnSO4, andwith other parameters ﬁxed. The fermented extract (FE) with IC50 value of 0.45 mg/ml showed the strongest antioxidant potency, compared to unfermented extract (UFE), with IC50 of 1.13 mg/ml, and the synthetic antioxidant, BHT, with IC50 of 0.63 mg/ml. The phenolic compounds were identiﬁed and quantiﬁed by HPLC. Ó 2010 Elsevier Ltd. All rights reserved.
Article history: Received 9 March 2010Received in revised form 27 July 2010 Accepted 10 August 2010
Keywords: Phenolics Liquid-state fermentation Aspergillus niger Palm oil mill efﬂuent Plackett–Burman design High-performance liquid chromatography
1. Introduction In Malaysia, the by-products of the palm oil industry have attracted considerable interest as a source of phenolic compounds, with much attention focused on palm oil millwastes. As the world’s second leading palm oil producing country after Indonesia, it is estimated that 0.5–0.7 ton of palm oil mill efﬂuent (POME) is discharged for every ton of oil palm fresh fruit bunches produced. In the year 2004, about 40 million tons of POME was discharged from 372 mills (Yacob, Hassan, Shirai, Wakisaka, & Subash, 2005). POME is highly polluting due to its organic nature andits discharge to a relatively small river can be devastating to its ecosystem. Several attempts have been made in the bioconversion of these palm oil wastes into fertiliser, fuel, water reclamation, citric acid, etc. (Alam, Jamal, & Nadzir, 2008; Vijayaraghavan, Ahmad, & Ezani, 2007). The production of phenolic compounds by utilising POME could provide a useful resource, as well as a proﬁtablemeans of waste management. Phenolic acids occur in free and bound forms. Free phenolic acids are located in the outer layer of the pericarp and are extracted using organic solvents. Bound phenolic acids are linked to various plant components through ester, ether or acetal bonds
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E-mail address: firstname.lastname@example.org (P. Jamal).0308-8146/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2010.08.022
ˇ ´ and typically involved in cell wall structure (Pericin, Krimer, Trivic, ´ & Radulovic, 2009). Acid and base hydrolysis is required to release these bound compounds from the cell matrix. The extraction yield of phenolic compounds is dependent on the method of extraction and hydrolysis,which should enable complete extraction of the phenolics, as well as minimising the oxidation, degradation, or polymerisation of the desired products (Zhao, Dong, Lu, Li, & Shan, 2006). Microbial fermentation through enzymatic hydrolysis offers an alternative to conventional extraction and hydrolysis methods. This technique is more environmentally friendly, decreasing the solvent consumption, and...