Baobab (adansonia digitata) seed as a source of biodiesel and protein hydrolysates: optimization of production processes and characterization of the products

Increase in global population places a demand on fuel and protein sources therefore putting a

strain on their supply. The demand for fuel products is currently met by increased usage of fossil

fuel, a nonrenewable energy source. However, burning of fossil fuel has challenges such as the

release of greenhouse gases associated with negative environmental impacts. To overcome these

challenges, attention has been given to renewable energy sources as biodiesel, a biofuel that has

good potential to replace petroleum diesel. Despite the attractive potential, its production is

hindered by different challenges such as the limited supply of feedstocks. Therefore,

identification of hitherto unexploited natural resources such as oil bearing plants could overcome

this challenge. Adansonia digitata is an under used plant that can be exploited and used as a

source of oil for biodiesel production. In this study, A. digitata seed oil was used to produce

biodiesel. The resulting biodiesel showed a density of 878 kg/m3

, a viscosity of 4.276 mm2

/s, a

cloud point of 5°C, our point of -11°C and an iodine number of 57.9. These values fall within the

international standards indicating its usefulness for fuel application. In addition to using the seed

oil for biodiesel production, the oil meal was used for the isolation of protein. The functional

properties of the seed protein exhibited properties that make it suitable for application in the food

industry. The protein has a water holding capacity of 1.29 g/g, water solubility index of 3.25 %,

oil holding capacity of 1.14%, foam capacity of 41% and a foam stability of 67%. This indicates

the potential usefulness of the seed protein. The protein was also enzymatically hydrolyzed and

used for microbiological growth as a peptone. The peptone was able to support the growth of the

test microorganisms the same as or better than commercial peptone. Utilization of the protein for

food and nonfood application could lower the production cost of biodiesel and help to generate

economic benefits to local communities. Therefore, further research leading to the production of

new products from A. digitata to better understand the biology of the plant is recommended.