Page 153 - Biofuels Refining and Performance

136 Chapter Four

Figure 4.22 Carica papayaL. (Photo
courtesy of Barbara Simonsohn
[www.barbara-simonsohn.de/
papaya.htm].)

of the proteolytic enzymes papain and chymopapain—the former find-
ing use in a wide range of industries, particularly brewing for haze
removal, and the latter in medicine. Oil extraction from the seeds could
improve the viability of the industry in countries where papaya is cul-
tivated for papain production and processing. The seeds constitute
around 22% of the waste from papaya puree plants [182]. No references
about its use as a biodiesel source have been found so far.

4.6.5 Sal oil
Crop description. Shorea robusta Gaertn. f.—commonly known as sal,
shal, saragi, sakhu, sakher, shaal, ral, gugal, mara, sagua, salwa, sakwa,
kandar, and kung—is a large tree belonging to the family Dipterocar-
paceae (see Fig. 4.23). The tree is native to southern Asia, ranging south
of the Himalayas, from Myanmar in the east to India, Bangladesh, and
Nepal. It grows in dry tropical forests, in a well-drained, moist, sandy
loam soil. This tree can attain heights up to 35 m. The seeds of sal are
an important source of edible oil. The seed contains around 20% of oil
[183, 184].

Main uses. Although sal is a highly valued timber species, it is also
used for house construction, and as poles, agriculture implements,
fuelwood, fencing, leaves for cups and plates, and compost [185]. The
oil is used for lighting and cooking purposes, and as a substitute for