Acta Astronautica 63 (2008) 1037–1042 www.elsevier.com/locate/actaastro Bioconversion of rice straw into a soil-like substrate

To increase the closure of bioregenerative life support systems (BLSS), the bioconversion of rice straw into a soil-like substrate (SLS) by mushrooms and worms has been studied. The results showed that rice straw could be treated better by aerobic fermentation and succeeding growth of mushrooms Pleurotus ostreatus. In this process the total content of lignocellulose in the straw was removed by 37.74%. Furthermore, 46.68 g (fresh weight) of mushrooms could be produced from 100.0 g (dry weight) of rice straw. During the conversion of rice straw into a starting SLS by mushrooms and worms, the matter loss was 77.31%. The lettuce has been planted in the SLS and the yield when lettuce was cultivated on the SLS (8.77 gm−2 day−1) was comparable to the yield obtained on the nutrient solution. In addition, the silicon in the SLS ash can reach upto 32 % and the circulation of it is expected during the growth of rice