Coconut oil extraction by the traditional Java method: An investigation of its potential application in aqueous Jatropha oil extraction

A traditional Java method of coconut oil extraction assisted by paddy crabs was investigated to find out if crabs or crab-derived components can be used to extract oil from Jatropha curcas seed kernels. Using the traditional Java method the addition of crab paste liberated 54% w w−1 oil from grated coconut meat. Oil extraction using crab paste carried out under controlled temperatures and in the presence of antibiotics showed that enzymes from crab played a dominant role in liberating oil from grated coconut meat and aqueous J. curcas kernel slurries when incubated at 30 °C or 37 °C. However, at higher temperature (50 °C), thermophilic bacterial strains present inside crabs played a significant role in the extraction of oil from both oilseeds tested. A thermophilic bacterial strain isolated from crab paste and identified based on 16s rRNA sequence as Bacillus licheniformis strain BK23, when added as starter culture, was able to liberate 60% w w−1 oil from aqueous J. curcas kernel slurry after 24 h at 50 °C. Further studies of BK23 and extraction process optimization are the challenges to improve Jatropha oil extraction yield and process economy.