Biodegradation of Palm Oil Mill Effluent.

Aims: The aim of this study was to investigate the biodegradation capacity of selected indigenous fungal isolates and optimization of their degradation ability using various environmental factors such as pH, incubation temperature, nutrient concentration and inoculums size in reducing pollution effect of palm oil mill effluent (POME) in the environment. Place and Duration of Study: Two fungal isolates Candida rugosa and Geotrichum candidum used in this work were previously isolated from POME sample collected from Starline palm oil mill industries, Umukalika, Obingwa LGA, Abia state Nigeria in previous work of authors. The study was carried out from March to August, 2013. Methodology: Spore suspension was prepared by adding 10 ml of 0.1% Tween 80 onto PDA slant of 5 days old culture of Candida rugosa and Geotrichum candidum respectively. Biodegradation of POME was carried out by inoculating 0.1ml (106spores/ml) of respective fungal isolates into different 500 ml Erlenmeyer flasks containing 100ml each of raw POME. They were incubated at 30ºC on a rotary shaker (200rpm). Samples were taken every 24hrs for 144hrs to determine BOD, COD, oil & grease. Similarly, optimization of biodegradation was carried out by studying the effect of different environmental conditions such as different initial pH levels (4.0-8.0), incubation temperature (25-50ºC), concentrations of soy bean (1.5-4.5% w/v) and inoculum size (0.1-0.5 v/v). The experiments were done in triplicates. Results: Biodegradation studies with selected indigenous fungi showed that C. rugosa was able to remove (44.6%) BOD, (13.9%) COD , (50.7%) oil and grease (O&G) while G. candidum reduced BOD, COD, O&G by 46.9%,16.9% and 64,9% respectively after 144hrs. Optimization of degradation in POME using various environmental and nutrients conditions revealed that at pH 8, C. rugosa showed best degradation of COD (48.6%), BOD (74.5%), O&G (41.8%) removal while COD (59.1%), BOD (75.7%) , O&G (59.1%) removal was observed with G. candidum treatment. The optimal incubation temperature for degradation using each of fugal isolates was at 35ºC with 85.2% BOD , 71.8% COD and 67.3% O&G removal for C. rugosa , 87.3% BOD and 63.4% COD for G. candidum .The best degradation ability for C. rugosa and G. candidum were demonstrated at 3.5w/v and 2.5w/v soybean concentrations respectively. The result also showed that increase in inoculum size could not completely reduce oil and grease during degradation process possibly because no single culture supports degradation optimally due to presence of complex sugars Conclusion: The selected fungal isolates exhibited high efficiency for removal of oil and grease as well as organic matter from POME but required control of environmental conditions and nutrient expansion for the effective biodegradation of POME.

Lipase Production by Fungal Isolates Grown in Palm Oil Mill Effluent.

Aims: The present work is aimed at determining the optimum conditions of pH, temperature and nitrogen concentration for lipase production by Candida rugosa and Geotrichum candidum in POME. Place and Duration of Study: This work was carried out at the Department of Microbiology, Michael Okpara University, Umudike-Abia state, Nigeria from July to December, 2013. The organisms used in the study were isolated in a previous work by the authors. Methodology: Five milliliter of sterile water was added to respective agar slant containing the two different fungal isolates while developed growth was scrapped with sterile needle and subsequently transferred into nutrient broth contained in 250 mL Erlenmeyer flasks. These flasks were further incubated for 48 h at 28ºC on rotary shaker at 180rmp. At this stage 0.1 mL of inoculum was transferred to the production medium (POME) and incubated for 144 h. Results: At initial pH6.0, C. rugosa produce maximum lipase activity of 26.37 UmL-1 while G. candidum showed highest activity of 29.4 UmL-1 at pH 7. C. rugosa alo showed maximum lipase activity of 27.8 UmL-1 at 30ºC while G. candidum produced highest lipase activity (24.9 UmL-1) at 35ºC. The use of soybean meal in the optimization of production lipase revealed that at concentration of 3.5%w/v, the respective fungi isolates were best supported for lipase yield with maximum activity of 25.97 UmL-1 by C. rugosa and 28.32 UmL-1 by G. candidum. Conclusion: This work evaluated the effect of three culture conditions (pH, temperature and nitrogen conc.) on lipase production by G. candidum and C. rugosa cultivated in POME. Results reveal that the factors were critical to growth and lipase production by the organisms and may be useful indices in the production of lipase even from other oil processing effluents.

Bioremediation of Industrial Solid Wastes.

Aims: Use of Pleurotus ostreatus as a veritable tool in the bioremediation of empty fruit bunches, pulp and paper wastes from respective industries. Place and Duration of Study: Samples of pure culture Pleurotus ostreatus was obtained from National Roots Crops Research Institute Laboratory Umudike, Umuahia and transported to the laboratory of Starline Nigeria Group of Companies Aba, both in Abia state, Nigeria where it was used to carry out experimental work from July to September, 2013. Methodology: The two substrates (empty fruit bunch (EFB) and paper pulp wastes) were dried in the sun for one week and further dried in Gallen Kamp hot box oven (DGH-9053A) at 50ºC for 4hours. Samples were ground, sieved and powder obtained used for proximate composition determination. Approximately 1cm2 blocks of pure culture of Pleurotus ostreatus mycelium previously collected and maintained on Malt extract agar (MEA) was used to inoculate sterilized wheat grain already soaked in water for 36hours, mixed with 2.5% calcium carbonate and 1% gypsum during spawn preparation. The empty fruit bunches and paper wastes were reduced to smaller sizes of 2-5cm. The respective substrates were mixed with lime and soaked in water for 4h to obtain moisture level of 70%. The substrates (2kg) was bagged in heat resistant polythene and sterilized for 3hours at 80°C. Approximately 40g individual sterilized substrate was inoculated with 2% spawn adopting multilayered technique. After inoculation, holes were made on the bags to ensure aeration, kept inside a disinfected room at 25-28ºC. When Pleurotus mycelium had completely colonized the substrates, bags were removed, colonized substrate transferred to sunlight illuminated room at 28°C, moisture content of 75-85% and adequate watering of the mushroom for 21 days. The process was repeated in combinations of other substrates like wheat, straw and sorghum respectively with each of the substrates (EFB and Paper Waste); all prepared at 70:30% ratio respectively. Results: Among the different treatments, Empty fruit bunch gave maximum yield of 201.5g/kg of substrate on 14th day and total yield of 675.1g/kg of dry substrate. The nutritional content of Pleurotus ostreatus grown on different substrate and substrate combination ranges from 83.5-91.4% moisture, 18.3-23.5% protein and 6.04-6.86% ash contents. The combination of EFB + sorghum best supported the bioremediation process of Empty fruit bunch. Conclusion: Pleurotus ostreatus could serve as bioremediation tool for industrial solid wastes like EFB and paper. It can also alleviate poverty by providing greater income for most unemployed youth at no cost.