Abstract: In order to provide a theoretical basis for growth regulation and efficient cultivation of Tremella fuciformis, the effects of different cultivation temperatures on seven extracellular enzyme activities at various growth and development stages and nutritional quality characteristics of Tremella fuciformis were studied. Meanwhile, the relative importance of seven extracellular enzymes for the nutritional quality of Tremella fuciformis was discussed by correlation analysis and path analysis. The results showed that the changes in the activity of extracellular enzymes of the same type were similar and the changes in all enzyme activities tested were stepwise in the appropriate temperature range. Comparative study revealed that the dry biological efficiency, polysaccharide content and protein content of mature Tremella fuciformis were the highest at (23.0 ± 0.5)℃ among seven cultivation temperatures, which were 35.67%, 21.51% and 8.53%, respectively. Correlation analysis showed that the average activity of all extracellular enzymes except carboxymethyl cellulase was positively correlated with dry biological efficiency and polysaccharide content, and protein content was positively correlated with the average activity of all seven extracellular enzymes. Further, path analysis showed that protease was a key factor for the nutritional quality of Tremella fuciformis. Collectively, these results indicated at (23.0±0.5)℃, the activity of key extracellular enzymes was higher and the nutritional quality of Tremella fuciformis was the best. Therefore, (23.0 ± 0.5)℃ can be recommended for industrial cultivation of Tremella fuciformis.

Key words: temperature, Tremella fuciformis, extracellular enzyme, enzyme activity, nutritional quality