1.1.1.1. Proteineous meal

The major biodiesel feedstocks are vegetable oils which are generally produced by crushing oil seeds, leaving significant quantity of proteineous meals as coproducts. The global con­sumption of proteineous meal in 2011/12 as reported by USDA Economic Research Services [97] is depicted in Figure 7 indicating soybean as the predominant crop producing proteineous meal with 67 % contribution. According to the FAOSTAT database [98], US, Brazil and Argentina were the global premiers of soybean production in 2010 with 35, 26 and 20% contribution, respectively. The next largest producer is China with almost 6% share in the global soybean production. In this context, biodiesel production of the US, as for example, has increased, during 2006-11 period, 340% from 250 to 1100 millions of gallons [99], which promoted the proteineous meal production. Soybean meal is traditionally used as a filler in animal feed including poultry, swine, beef, dairy, pet and other animals due to its concentrated protein content (Table 1).

Other examples of plant-based feedstock potentially suitable for oil extraction and biodiesel production can be listed as canola and linseed [100], palm [101], karanja [102] and jatropha [103]. Jatropha is a non-edible seed from a large shrub commonly found throughout most of the tropical and subtropical regions of the world. As shown previously in section 2.1, jatropha is projected to have a 3.2 % contribution in biodiesel production by 2020. The growing utilization of plant-based feedstocks other than soybean meal in biodiesel production also brings new streams of proteineous meal as coproducts.