TECHNOLOGY FOCUS - BIOLOGY - Preparation: Production of novel salt tolerant oyster mushroom strain Pleurotus ostreatus DH-1012 comprises:(a) culturing numbers of hyphae in the composts with different salt concentration and selecting hyphae that are less affected by higher salt concentration in growing;(b) obtaining numbers of strains by separating monospores from the selected hyphae in an aseptic condition and then inducing mutation by irradiating ultraviolet rays;(c) selecting an auxotroph strain having fertility among the mutation induced strains;(d) obtaining numbers of strains by selecting one among high quality oyster mushrooms and separating monospores, then inducing mutation by irradiating ultraviolet rays;(e) selecting an auxotroph strain having fertility among the mutation induced strains; and(f) producing a somatic cell hybrid strain by monospore mating between the strain selected in the first and second selection steps.Preferred Materials: The strain in the culturing step is Pleurotus ostreatus. The strain used in the second obtaining step is Pleurotus ostreatus Nonggi 2-1.Preferred Method: The hyphae are cultured in the PDA (sic) composts while varying the salt concentration by 0.5% within 0-3%, and a hyphae whose growth is less affected by the variation/increment of salt concentration is selected.    TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The method further comprises a specialty additive producing step for producing specialty additive, which is used for mixing with other feeds and organic fertilizers, with the compost remaining after harvesting the cultivated mushrooms. It further comprises a manure producing step for producing manure with the compost remaining after harvesting the cultivated mushrooms. The food wastes pre-processing step comprises eliminating foreign metallic objects from food wastes, crushing the food wastes from which foreign objects have been eliminated into a predetermined size, and deodorizing the crushed food wastes, where the mushroom cultivating step comprises:(a) forming a compost by mixing dry cellulose with food wastes so that water content of the crushed food wastes from which foreign objects have been eliminated is 50-70%;(b) inserting a predetermined amount of the formed compost into the cultivating vessel;(c) sterilizing the compost by supplied steam from the boilers at 60-121 degrees Centigrade for 1-5 hours;(d) cooling the compost down to 20-25 degrees Centigrade;(e) inoculating a predetermined amount of the novel strain Pleurotus ostreatus DH-1012 into the compost; culturing the strain for 15-30 days in an aseptic culturing room at 20-25 degrees Centigrade;(f) cultivating the cultured strain at 8-18 degrees Centigrade; and(g) harvesting the mushroom; and the specialty additive producing step comprises separating the compost remaining after harvesting the mushrooms from the cultivating vessel;(h) crushing the separated compost into a predetermined size;(i) eliminating foreign objects from the crushed compost; and producing specialty additive by drying the foreign objects eliminated compost so that the water content of the compost is 10-15%. EXAMPLE - 26 kinds of oyster pleurotus were collected and tested in different growing conditions. For the hyphae growing temperature, the hyphae were grown in the PDA composts with 5 degrees Centigrade variations at 10-35 degrees Centigrade. Hyphae were again grown with 1 degrees Centigrade variations for testing an operation hyphae growing temperature in the best temperature range. The hyphae were cultured in the PDA composts with increasing salt concentration by 0.5% respectively at 0-3% and the hyphae, No. 12 Pleurotus ostreatus which was less affected in growing by the increased salt concentration was selected and named P. ostreatus-12. Monospores of the P. ostreatus-12 were separated and 76 strains were obtained. Strain No.38 was selected as an auxotroph. From the oyster mushroom P. ostreatus Nonggi 2-1 monospores were separated and 82 strains were obtained. Strain No. 16 was selected as an auxotroph. By monospore mating between P.ostreatus-38 and P. ostreatus-16, an oyster mushroom strain P. ostreatus DH-1012 which was a somatic cell hybrid with salt tolerant capability and high quality was obtained.