Evaluation of Three Kinds of Nutshell with Respect to Utilization as Culture Media

Abstract

The material basis of nutshells was explored in this study for Camellia oleifera Abel, Castanea mollissima Blume, and Carya cathayensis Sarg., The authors measured the moisture content, pH, electronic conductivity (EC), seed germination index (GI), and tannin content of the fresh shells of these three species. The contents of cellulose, hemicellulose, lignin, organic extracts, ash, saponin, cellulose crystallinity, organic carbon, and mineral elements of the dried shells was also measured. The results showed that the total mass fractions of cellulose, hemicellulose, and lignin in the shells of the three species were all above 80% of dry weight; the content of organic matter was higher than 66%, and the pH values were in the range of 5.5 to 8.5. The shells of the three species are good raw materials for the growth of plants and edible fungi. There were some shortcomings if used as fertilizers or substrates. However, the C/N and C/P ratios were high, the EC values were low, and the GI was < 100%. Additionally, the shells all contained tannin, saponin, and alkaloids, which were not conducive to the growth of plants and mycelia of edible fungi. Therefore, they can be used as culture media only after being processed.