title: Growth of rhizobia in protein hydrolysates.
abstract: Sixteen nitrogen-rich agricultural and industrial wastes and by-products, such as vegetable waste, lasora (Cordia myxa L.), meat waste, water-hyacinth (Eichhornia crassipes), and pea (Pisum sativum L.) husks were partially hydrolysed to amino acids with the help of acetic acid of 1, 5, 10, 15, and 20% concentration. In general, 10-20% acetic acid gave the highest amounts of amino acids. Each protein hydrolysate, separately or/and in proper combination, was substituted with the nutrient yeast extract in equal concentration (mg/ml) in yeast extract mannitol (YEM) medium. The growth of Rhizobium spp. was observed over a period of 5 or 7 days with determination of turbidity at 700 nm. High optical densities, but somewhat inferior to the control, were obtained in the case of medium consisting of hydrolysate of water-hyacinth, vegetable waste, pea husk, mixed leaves, and corn steep liquor substrates separately at different concentration of acid, but the medium consisting of hydrolysates of pea husk and water-hyacinth (5% acetic acid) in equal proportions showed similar growth to that with the YEM medium in the case of both Rhizobium spp.
mesh_terms: D000085:Acetates; D000383:Agriculture; D006868:Hydrolysis; D007220:Industrial Waste / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D011506:Proteins / Q000378:metabolism*; D012231:Rhizobium / Q000254:growth & development* / Q000378:metabolism; D014866:Waste Products / Q000032:analysis
chemical_list: D000085:Acetates; D007220:Industrial Waste; D011506:Proteins; D014866:Waste Products; D009584:Nitrogen