Jatropha Curcas

SUPPORTING NEW GENERATION BIOFUEL
  • Scientific name: Jatropha curcas
  • Common names: Physic nut, purging nut
  • Family: Euphorbiaceae
  • Origin: Mexico and Central America (??)
  • Occurs wildly in almost all tropical and sub-tropical countries of the world
  • Perennial shrub – grows up to about 5-6m height
  • Grows well in warm tropical climates
  • Plant is drought tolerant, adaptable and thrives on nutrient poor soils
  • Flowering and fruiting seasonal usually connected to the rainy seasons
  • Fruits containing 2-4 seeds, usually 3.
  • Dry fruit weighs about 2.5g, 60% weight seeds and 40% weight fruit husk
  • The seeds contain about 37.5% by weight shell, 30-40% oil and the rest mostly protein
  • Traditional uses: fence plant around small farms, medicinal purpose, non-toxic variety (called Xuta in Mexico) used as human food in Mexico
  • Pollination is by insects, usually honey bees
  • The plant, even the non-toxic variety, is non-edible to grazing animals, but honey produced from it is edible
  • Conventional, toxic Jatropha plants are familiar backyard and fence plants in many countries and people are familiar with it and its non-edible nature.

Jatropha plantation products

Pruned biomass:

to keep the plants at a height of about 2m, pruning would be required every year. Depending on plant nature and size between 1.5 and 5kg dry matter would be generated from 1 plant through pruning

Jatropha fruit fractions:

the major production item from the jatropha plantation are the fruits. They yield the following fractions on processing.

Freshly harvested fruits

Dried fruits – 3 days of sun drying

Fruit Husks

The fruits can be mechanically shelled using simple locally made machinery. Both fresh and dried fruits can be de-husked. The wet husk is ideal for mulching the plantation. For dry fruits mulch forms about 40% w/w. Dry husk has an energy content of 14MJ per kg and can be used as burning fuel.

The seeds form 60% /w of the dried fruits. They can be mechanically shelled into Shell and kernel

Jatropha shell (mechanically shelled) forms about 37.5% of the dry seed. It has a high energy content of 18MJ/kg and is a good burning fuel

Kernel forms about 62.5% of the dry seeds and can be crushed to separate oil and kernel meal

Jatropha oil forms about 60% w/w of the kernel and is an ideally fuel oil and feed stock for bio-diesel and bio-aviation-fuel. Non-toxic jatropha oil has potential to become an ideal edible oil.

Average fatty acid composition (%) of Jatropha curcas seed oil

Oleic acid (C-18:1) 35-51%
Linoleic acid (C-18:2) 27-42%
Palmitic acid (C-16:0) 9-22%
Stearic acid (C-18:0) 5-8%
Arachidic acid (C-20:0) 0-2%
Myristic acid (C-14:0) 0-2%
Palmitoleic acid (C-16:1) 0-1%

Typical physical/chemical properties of Jatropha curcas seed oil

Calorific value37.8 MJ/kg
AppearanceLight yellow liquid
Specific gravity at 30°/30°0.92
Acid value1.24
Saponification value197
Iodine value102
Unsaponifiable matter0.004

Non-toxic jatropha kernel cake forms about 40% w/w of jatropha kernels, contains about 60% crude protein and is an ideal animal and fish feed ingredient. Its protein have a high nutritional quality also for humans.

Conventional toxic jatropha seeds are crushed without deshelling, yielding about 28% w/w of oil and the rest seed cake. This contains 3-4.5% N, 0.65-1.2% P2O5, 0.8-1.4% K2O and 0.2-0.35% S and has been scientifically proven to be an excellent organic fertilizer. The phorbol esters present in the seed cake act as a biological pesticide particularly against soil nematodes, slugs and snails that are harmful to plants.