Organisms Associated With Palm Oil Fruit
Oil palm (Elaeis guineensis ) is a cross-fertilising arborescent monocot of the genus Elaeis that originates from West Africa (Hartley, 1988). Its diploid genome consists of 16 homologous chromosome pairs (Schwendiman et al. 1982). Its physical size estimated by flow cytometry is 3.9 pg/2C (Rival et al. 1997). Oil palm is the world’s leading source of vegetable oil and fat with an annual production of 40 million tons of palm oil along with 4.4 million tons of palm kernel oil. For the best varieties oil yields per hectare are ten times greater than soybean yields.
The fruit of oil palm is a drupe. It is made of pulp (mesocarp) from which palm oil is extracted, an endocarp called the shell, and a kernel that also contains oil. Three fruit varieties exist due to a major bi-allelic co-dominant gene called Sh, which controls the presence or absence of the shell and the degree of endocarp lignification. The dura type (genotype Sh+/Sh+) produces large fruits with a thick shell and relatively little mesocarp in weight terms. The pisifera type (genotype Sh−/Sh−) is usually female-sterile, and its rare fruits are relatively small, without any apparent shell and with a relatively large amount of mesocarp. The tenera type is the hybrid Sh+/Sh− genotype with fruits that have a shell of intermediate thickness and they contain abundant mesocarp. The tenera varieties, naturally more productive for palm oil, are the commercial varieties that are improved and distributed to planters.
For optimal growth and production the crop requires a high and year-round rainfall with little or no dry season and stable high temperature. Soils should be deep and well drained. The crop grows mainly in tropical lowlands below 400m altitude, originally covered by a dense rainforest. Dry spells or temperatures below 18°C do not affect vegetative growth but reduce yield. Oil palm is now the most important supplier of vegetable oil in the world. There are three oil palm varieties: dura, pisifera and tenera, with the latter being mainly selected for economic production. The oil is concentrated in the fruit bunches, composed of a fresh fruit pulp, and in the fruit kernels. Oil content in the fruit pulp is about 50-60% or 20-22% of bunch weight; oil content in the fruit Palm oil has for a long time been considered a relatively low-value edible oil because of the difficulty in manipulating its fatty acid profile.
According to Usoro (1974), the production and processing of oil palm constitute important sources of employment to many rural dwellers that own wide groves of less than 2 hectares. The trees are of unimproved varieties that have low yield and limited resistance to diseases,
and take about eight to ten years to mature, growing over 30 feet high with an average yield of 1.21 bunch weight (Njoku, 1990). The height of the trees make harvesting very difficult especially during the rainy season, when climbing becomes almost impossible.
1.2 Biodiesel from oil palms
Oil palm is among the most productive and profitable of tropical crops for biofuel production. High-yielding oil palm varieties developed by breeding programs can produce over 20 tonnes of fresh fruit bunches/ha/yr under ideal management, which is equivalent to 5 tonnes oil/ha/year (excluding the palm kernel oil). The oils form 10 per cent of the total dry biomass produced by the palm, while the 90 percent left might be a source of fibre and cellulosic material for second-generation biofuel production (Basiron, 2007). Production of biodiesel from oil palm has been increasing in recent years, particularly in Africa and Latin America (Mitchell, 2011). Traditionally, oil palm production was managed as part of mixed farming practice in West Africa. Today, most production is being expanded as an industrial-scale mono-crop, imposing significant environmental risks as well as impacts on local societies, particularly for people with limited economic capacities (Colchester, 2010). Modern oil palm cultivation is generally characterized by large monocultures of uniform age structure, low canopy, sparse undergrowth, a low-stability microclimate and intensive use of fertilizers and pesticides (Fitzherbert et al., 2008). The oil palm tree generates fruits from the third year, with yield per tree increasing gradually until it peaks at approximately 20 years (FAO 2002). Hence, oil palm plantations are typically destroyed and replanted at 25 to 30 year intervals (Wahid et al, 2005). The process of palm oil production tends to reduce freshwater and soil quality, and adversely affects local communities which are dependent on ecosystem products (such as food and medicines) and ecosystem services (such as regulation of the hydrological cycle and soil protection) provided by the forests (Fitzherbert et al, 2008). From an ecological point of view, oil palm monocultures might form impervious barriers to species’ migration and result in greater susceptibility to plant diseases. Palm oil seed cultivation and harvesting are predominantly performed by manual labour, creating one job for every 2.3/ha. A major challenge is to implement regulations and procedures to address problems such as the inequalities between small-scale, often informal producers, and large ,trans-national oil palm enterprises (Colchester, 2010). The environmental impacts of palm oil production and use can be assessed from a life-cycle point of view. This means carrying out a holistic perspective in which emissions are taken into account, from the raw material extraction to the recycling or disposal stages. Impacts depend greatly on the land-use change conditions, the consumption of conventional fuels, fertilizers, pesticides and the wastes generated (Menichetti et al., 2008). The environmental sustainability of palm oil-based biodiesel production is determined by four factors: (1) land-use change; (2) soil quality; (3) biodiversity and (4) water quality impacts (Stichnothe et al, 2011). Land-use conversion from forest to oil palm is perhaps the most important criterion when evaluating environmental sustainability with respect to greenhouse gas (GHG) emissions. Degraded agricultural lands contribute to biodiversity loss, increased soil erosion, nutrient loss and GHG emissions. Notably, biodiesel from palm oil that is used as a low-carbon alternative to gasoline often contributes far more GHG emissions to the atmosphere than it is replacing when the plantations producing the palm oil were established by deforestation (Menichetti et al., 2009; World Bank 2010).
1.3 Objective of the study
- To find out the organisms associated with palm oil fruit.
- To isolate and identify those organisms.