Bio-Composting Process Development by SSF for Utilization Agro-Industrial Wastes N.A. Kabbashi1, MD.Zahangir Alam 1 and Muhammad Ainuddin2 1
International Islamic University, Bioenvironmental Engineering Research Unit (BERU) Department of Biotechnology Engineering, 50728 KL, Malaysia 2 International Islamic University, Department of Biotechnology Engineering, 50728 KL, Malaysia
Abstract— The wastes derived from oil palm industries are generated every year and becoming a great concern, consequently, an urgent development of bio-composting process has been investigated. Bio-composting is an environmental friendly bioconversion process where its products could be utilized as plant growth enhancement. In Malaysia about 50 million tons of Palm Oil Mill Effluents (POME) and about 40 million tones of Oil Palm Biomass (OPB) in forms of empty fruit bunches (EFB), oil palm trunks (OPT), and oil palm fronds (OPF) are generated from palm oil industries every year, the management practice pose significant environmental problems. This study was concerning about simple composting process using selected substrates, POME and EFB plus wheat floor as a cosubstrate. The strains of P. chrysosporium, T. harzianum, A. niger (A 106, S 101), and Penicillium isolated from POME were used for effective bio-composting process. Tray bioreactor was used to evaluate the efficient composting process through solid state bioconversion. The composting time required to complete the process was two months and some parameters were determined to evaluate the compost quality. In the entire process merely, percentage of OM decreased to about 3% while total nitrogen content initially at 0.744 g/g increased to 2.96 g/g. The C/N ratio and GI achieved were 17 and 95 % respectively. The maturity of the compost could be reflected by C/N ratio, pH and GI measurement. The use of POME and EFB as mixed substrates with the induced microorganisms is a new composting trial where it has been expected to receive a good result in order to overcome a conventional composting process. Keywords— Oil palm waste, microorganisms, C/N ratio, SSF, GI.
I. INTRODUCTION Since early 70s, palm oil industry has emerged as one of top industry in Malaysia and as a result many palm oil factories had emerged to process these fruits. The production of crude palm oil involves mechanical extraction process in which the fresh fruit bunches undergo sterilization, digestion and extraction of the oil. However, all of these processes generate palm oil mill effluent (POME) in which affecting the environment [1]. The environment had to be jeopardize in order to get highest profit. The suspended solids in POME are mainly oil-bearing lignocellulosic mate-
rials that come from fruit. Lignocellulosic is the major structural component of woody plants such as grass and represents a major source of renewable organic matter. Lignocellulosic consist of lignin, hemicellulosic, and cellulosic material. The chemical properties of the components of lignocellulose make them a substrate of enormous biotechnological value. The palm oil industry in Malaysia produces about 90 million tones of lignocellulosic biomass [2] . For instances, the oil palm biomass (OPB) produces about 40 million tonnes per year. This OPB can be categorized as a form of empty fruit bunches (EFB), oil palm trunks (OPT) and oil palm fronds (OPF) and the rest are palm oil mill effluent (POME). There are 7.0 million tones of oil palm trunks, 26.2 million tones of palm oil fronds and 23% of empty fruit bunch (EFB) per tone of fresh fruit bunch (FFB) processed in oil palm mill for re-plantation after about 20 to 25 years [3]. Much of the lignocellulosic waste is disposed by biomass burning, which is not restricted to developing countries alone, but it is considered a global phenomenon. In addition, the problem arises when all of this biomass is not being treated and left to rot in the plantations to provide some nutrient. Unfortunately, these wastes may create the environmental problems later due to high organic content accumulate on the ground. Therefore, environmental management is placing the greatest emphasis in waste minimization at source or recycling. Moreover, a growing awareness of the need not to pollute has forced this industry to look more closely at the milling operation. It is recommended to treat and manipulate the waste to produce the useful product. Therefore, bio-composting process promises a high potential on sufficiently solving the abundant wastes from agroindustries where in many cases, composting provided a viable alternative method for managing organic wastes [4]. Agro-industrial wastes are being produced or generated million tones per year such as waste from palm oil industries where it is estimated over 90 million tones were produced through out a year. The management of agroindustrial wastes should be selected with suitable techniques and technologies to minimize waste generation or re-use or recycling them to be raw materials for other productions. Wastes, if not efficiently maintained or treated, will create
F. Ibrahim, N.A. Abu Osman, J. Usman and N.A. Kadri (Eds.): Biomed 06, IFMBE Proceedings 15, pp. 464-468, 2007 www.springerlink.com © Springer-Verlag Berlin Heidelberg 2007 ---------------------------------------------------------------- IFMBE Proceedings Vol. 15 ---------------------------------------------------------------
Bio-Composting Process Development by SSF for Utilization Agro-Industrial Wastes
II. MATERIALS AND METHODS Two bulk materials were used, which are palm oil mill effluent (POME) and empty fruit bunch (EFB). The equipment setup, samples, chemical and reagent, microorganisms and media composition were selected based on literature reviews. In general, sterilization is not required to fulfill this project. Substrates and Co-substrate Palm oil mill effluent (POME) and oil palm biomass (OPB) were obtained from a local palm oil mill manufacturer (Seri Ulu Langat Palm Oil Mill at Dengkil, Selangor, Malaysia). Co-substrate used in the experiment was wheat flour, for effective biodegradation of STP (sewage treatment plant) sludge compost using filamentous fungi [6]. Fungal Strain Four different types of microorganisms had been used, served different function in biodegradable process. There were Penicilium, Aspergillus, Tricorderma, and Phanerochaete chrysosporium. The fungi were separated and maintained on Potato Dextrose Agar (PDA) plates for spore production and were incubated at 32°C until the entire plate is discovered by fungus. The best grow of the fungus were at seventh day. Experimental procedures According to the research done before, 50 L capacity of solid-state horizontal rotary drum bioreactor is the most suitable to perform this project. The period of incubation was two months where the sampling will be taken from 0, 10, 20, 30, 40, 50 and 60 day. Fermentation was done inside the solid-state horizontal rotary drum bioreactor. The process conditions set up for the process were maintained, included the pH which is in the range 5-7, temperature was at the ambient temperature (30 + 2 oC), the moisture condition at 60-70%, the agitation was 10 minutes per day, and the aeration was 1 hour per day. The inoculum used was cultured inoculum about 5-10%.
III. RESULTS AND DISCUSSIONS The experiment was carried out in the horizontal rotary drum bioreactor with the substrate and co-substrate which undergoes composting process for 60 days. Several fungi were inoculated inside the bioreactor that affects the result of compost. The mixing of the compost was done by rotating the bioreactor at 10 rpm for 10 minutes once a week through agitation. Whereby, the aeration was accomplished by means of an air compressor in which the air is sterilized by bubbling through sulphuric acid (2%) everyday. pH of the water extract From Fig.1, pH of the compost initially was 5.71. Within the composting period, the pH did not change very much and in the range of 5-6. This result may be described by [7] as the effect of the production of organic acids inside the bioreactor. As the next 20 days the pH is almost same, then it start to increase gradually at days 40 as the pH showed 6.4. The increasing phase of pH in alkaline was attributed to ammonification and mineralization of organic nitrogen through microbial activities. As the pH reached the highest point, it started to decrease to 5.6 at day 50 and 60. 7
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mass problems that include human, living organisms, and environment. Compost is a product produced ecologically and economically through chemical, physical and biological activities. Composting is commonly defined as a natural aerobic biochemical process in which thermophilic microorganisms transform organic materials into a stable soil-like, product. The process is well established and has been comprehensively documented in several literatures. Factors that influence microbial activity include temperature, oxygen concentration, pH, moisture content, carbon to nitrogen (C/N) ratio and particle size [5].
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Color intensity/optical density of the water extract Color intensity or optical density (OD) measurement is recognized as the most reliable parameter and more or less free from conceptual deficiencies compared to other estimation of the rate of biodegradation or compost maturity [8]. The OD of the water extract of compost at fixed wavelength could be appropriate test for compost biomaturity.
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Glucosamine assay From Fig. 4, the glucose increased at the initial phase (day 10 and day 20) before it started to decrease between days 20 to 40 of composting time. The glucose concentration was increased at day 50 before started to decrease at day 60. This can be related due to the reduction of nutrients for the growth of fungi.
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Fig. 2 Color intensity/OD profile
As in Fig. 2, the OD increase from 0.5 to 0.7 for the first 10 days and then increase to 0.8 for the next 10 days. From the figure, it can be seen that the OD is fluctuate within the composting days where the value start to decrease after day 20 and increase back at day 50. This fluctuation value can be described as the non-homogeneous product was taken during sampling time. The color of the water extract was changing to be darker as means of the presence of biomass and biochemical. The color was changed according to the growth of the fungal cells and spores. In composting process, different polymers, phenols, and organic acids are metabolized to secondary products and mineralize into simpler stable product [8]. Thus, [6] notified that the water extract of compost may have those organic constituents along with microbial cells and spores. Protein assay Protein assay is used as an indication of fungal biomass production which is positively correlated to soluble protein production in solid state bioconversion [9]. For this analysis, the protein assay was done in two distinctly experiment using the water extract and the solids material of the compost as seen in Fig. 3. 1.400
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Fig. 4 Glucosamine assay as biomass indicator
It was a good compound to estimate the produced biomass from microorganism’s growth. [6] described that glucosamine can be considered as a good parameter for estimation of the mycelia growth in solid substrate. Where, glucosamine is an essential component in chitin of mycelia cell wall, is a water soluble sugar and stable component. The accuracy of the glucosamine method in determining the fungal biomass depends on establishing a reliable conversion factor relating glucosamine to mycelia dry weight [4]. Organic Matter Organic matter (OM) profile from Fig. 5 below showed that the OM content gradually decreased as the biodegradation time increased. The degradation of OM was related to the growth of microorganisms where [6] recorded in the bioconversion or composting process, the organic substrates were degraded into stabilized product. Hence, it also reduced the weight of the substrates.
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F. Ibrahim, N.A. Abu Osman, J. Usman and N.A. Kadri (Eds.): Biomed 06, IFMBE Proceedings 15, pp. 464-468, 2007 www.springerlink.com © Springer-Verlag Berlin Heidelberg 2007 ---------------------------------------------------------------- IFMBE Proceedings Vol. 15 ---------------------------------------------------------------
Bio-Composting Process Development by SSF for Utilization Agro-Industrial Wastes
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C/N ratio [10] described that the C/N ratio is an index traditionally used to evaluate the maturation of the end product (compost) of bioconversion, but the value cannot be used as an absolute indicator of compost maturation. The maturity of the compost is the important parameter in compost production process and its application. One of the practical ways is using C/N ratio evaluation, the C/N ratio is also widely used as an indicator of compost maturation and should become stable with time.
Temperature profile For this study, there were no much differences in temperature during treatment period. The temperature was 27.5 at 0 day and increase to 27.8 at day 10 before decreasing to 27.4 at day 20. The stable value in temperature can be describe as high humidity, very closed and confined vessel. The temperature increase indicate the growth of microorganism inside the bioreactor generate heat during composting period.
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IV. CONCLUSIONS AND RECOMMENDATIONS
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Fig. 6 Changes in C/N ratio profile of composting process
Germination Index (GI) Germination index (GI) is the most sensitive parameter used to determine the level of toxicity of composts to seedlings and it is to test if the compost is mature [11] and [12]. In Fig. 7, the GI was at 48% in the zero days and slightly increased to 50% at day 10 of composting. By the inoculation of Penicillium at day 45, the GI was slightly increased to 60% and continuously increased within the treatment period. A GI value of 50 % has been used as an indication of phytotoxic-free compost [11], and a GI of more than 80 % is considered mature compost [13]. From this result, it can be concluded that the compost product is phytotoxic-free but yet is immature.
The study of the bio-composting process by solid-state bioconversion utilizing palm oil mill effluent (POME) and empty fruit bunch (EFB) were studied in lab scale (70 Litre Fermenter). From the research it is found that horizontal rotary drum bioreactor was the most suitable to run this study. Moreover, the batch process was conducted to run the experiment under unsterilized conditions. To make this solid-state bioconversion using composting technique become effective, several parameters were controlled instead of optimizing the process condition. pH, temperature, the moisturization, agitation and aeration. The inoculum used was cultured inoculum. The study was carried out by utilizing POME and EFB as main substrates, wheat flour as a co-substrate, and undergoes composting process for 60 days inside horizontal rotary drum bioreactor. In addition, the inoculation of microorganisms likes Phanerochaete chrysosporium, Trichoderma harzianum, Aspergillus niger, Penicillium sp help to achieve good compost. The end product can be considered as good compost when several parameters like the C/N ratio, GI and glucosamine assay met their standard. The C/N ratio range from 25 to 30, the GI is up to 70% which is phyto toxic free and merely become mature compost. In this study, 4 different microorganisms were used,
F. Ibrahim, N.A. Abu Osman, J. Usman and N.A. Kadri (Eds.): Biomed 06, IFMBE Proceedings 15, pp. 464-468, 2007 www.springerlink.com © Springer-Verlag Berlin Heidelberg 2007 ----------------------------------------------------------------- IFMBE Proceedings Vol. 15 ----------------------------------------------------------------
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N.A. Kabbashi, MD.Zahangir Alam and Muhammad Ainuddin
and only Trichoderma harzianum were isolated from the POME. Other microorganisms like Phaneochareate chrysosporium, Penicillium sp and Aspergillus niger were cultured from single strain. The study can be improved by using the mixed culture, which can give a good degradation of cellulose and hemicellulose by producing cellulolytic enzyme. The study can be improved also by optimizing process condition to enhance the bio-composting process by solid state bioconversion
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ACKNOWLEDGMENT The authors wish to express their sincere thanks to IIUM, Kulliyyah Engineering, and department of Biotechnology engineering for sponsoring the project and helping during running the experiments.
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[email protected]
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