Coating seeds with biopolymers extracted from waste-activated sludge

Seeds can be coated with biopolymers extracted from waste-activated sludge, and the seeds of lettuce and spinach can be coated. When coated with the biopolymers, these seeds exhibited largely improved resistance to high temperature and humidity. The seeds coated or not coated with the biopolymers were aged, and the germination potential, germination ratio, and antioxidant enzyme activity of the coated seeds exhibited markedly greater differences than did those of the uncoated seeds. Moreover, the CAT, POD, and APX activities in the coated lettuce and spinach seeds increased by 56%, 2%, and 17%, respectively (lettuce), as did the activity of 8%, 3%, and 31%, respectively (spinach). In the pot trials, the contents of soluble protein and soluble sugar and the activities of antioxidant enzymes were also enhanced—42% and 56% (lettuce) as well as 34% and 23% (spinach). Thus, biopolymers can contribute to protecting against the aging of some rare seeds.