Aerobic Treatment And Biodegradation Of Palm Oil Mill Effluent By Indigenous Microorganisms
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Date
2016-02
Authors
David, Bala Jeremiah
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
Microbial biodegradation of wastewaters involving the application of variety of microorganisms has demonstrated effective degradability of organic wastes in wastewaters which has attracted attention in recent time. This study was designed to determine the biodegradation ability of indigenous microorganisms isolated from palm oil mill effluent (POME) as substrate for the reduction of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS) and oil and grease (O & G) from POME and to identify the most suitable strain(s) for a biological treatment technology of POME under aerobic condition. The characterization of POME sample was carried out according to standard methods for the examination of water and wastewater. Isolation and identification of indigenous microorganisms was subjected to standard microbiological methods and sequencing of the 16S rRNA and 18S rRNA genes respectively. Enzymatic activities of the isolated microbes were examined for the detection of lipase and cellulase on solid media by plate assay. Percent reduction of BOD5, COD, TSS and O & G by selected isolates was determined. HPLC analysis was carried out to indicate cellulose degradation. Sequencing of the 16S rRNA and 18S rRNA genes of the isolates suggests that they were identified as Micrococcus luteus 101PB, Stenotrophomonas maltophilia 102PB, Bacillus cereus 103PB, Providencia vermicola 104PB, Klebsiella pneumonia 105PB, Bacillus subtilis 106PB, Aspergillus fumigatus 107PF, Aspergillus nomius 108PF, Aspergillus niger 109PF and Meyerozyma guilliermondii 110PF. All identified isolates were screened for lipid hydrolysis and cellulolysis of cellulose by plate assay. Strains showed varying degree of lipase and cellulase activity on solid media. Growth profile of the bacteria and fungi isolates was conducted in mineral salt medium (MSM) liquid medium. Micrococcus luteus 101PB, Stenotrophomonas maltophilia 102PB, Bacillus cereus 103PB, Bacillus subtilis 106PB, Aspergillus fumigatus 107PF and Aspergillus niger 109PF were able to display comparable good growth and degradation of oil and cellulose in MSM and were selected for POME inoculation and reduction of organic load. Results revealed that the physicochemical parameters (COD, BOD5,TSS and O&G) were reduced remarkably with aerobic treatments. Percent reduction of the parameters by the microbial isolates (individual and combination) ranged from 35.93% – 95.20% for bacteria and 43.09 – 92.37% for fungi and 84.45 – 92.23% for mixed combination. Analysis of variance (ANOVA) showed that there were significant differences (P<0.05) in the percentage reduction of the parameters for Bacillus cereus 103PB and Aspergillus niger 109PF as compared to other isolates. Mixed cultures of bacteria and fungi in the present study showed high significant differences (P<0.05) in the percentage reduction of the parameters as compared to pure single cultures and were the most effective. Analysis of variance (ANOVA) also revealed that there were significant differences (P<0.05) in reduction of the parameters for temperatures at 37°C and 30°C for bacterial strains while no significant differences (P>0.05) in the rate of reduction of the parameters for temperatures at 28°C and 30°C for fungal strains. Non-sterile POME sample showed significantly higher reduction of the parameters than sterile POME sample. The breakdown of cellulose which represents the cellulosic materials in POME by microorganisms into glucose suggests biodegradation of cellulose. The study would help in understanding the role of indigenous bacteria and fungi isolated from POME in biological treatment of wastewaters such as those of oil processing like POME.
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Keywords
Biodegradation