Study On The New Fermentation Technology Of Cellulolytic Strains

The traditional modes of fermentation for producing cellulase including Solid Substrate Fermentation(SSF), Submerged Fermentation(SF), and a novel mode, Solid Substrate-Submerged Fermentation(SSSF), which was designed in this paper were systemataically studied from three parts of enzyme activity of single culture, mixed culture and recovery rate of cellulase. At the same time, we discussed the influence of two sorts of extractants and eight sorts of nitrogen sources on testing of cellulase activity. The main results showed: 1. In the past, the cellulase activity was different when researchers adopted buffer and pure water to extract the cellulase, respectively. However, according to the experiment, the cellulase activity of H8 and Q1 were higher when using pure water as extractant than buffer in the vitality test of cellulase. When extracting gross cellulase from the fermentation products, the time of extraction should be controlled about 45minutes, and too long will lead to the reduction of enzyme activity. 2. The SSSF is a new fermentation technology, which integrates the advantages of SSF with SF perfectly, and improved the cellulase activity in the process of fermentation. ①In the single culture, the SSSF made the FPA, CMC-Na and AVI of H8 increase averagely by 166.7 percent, 264.0 percent, and 273.6 percent, respectively, compared with SSF; and increase averagely 798.1 percent, 2325.5 percent, and 547.6 percent, respectively, compared with SF. Similarly, compared with SSF, the FPA, CMC-Na, and AVI of Q1 improved averagely 185.2 percent, 240.6 percent, and 257.9 percent, respectively if adopting SSSF; and improved averagely 1161.3 percent, 2798.0 percent, and 419.5 percent, respectively, compared with SF. ②　In the mixed culture, compared with SSF, the average improvement of FPA, CMC-Na, and AVI of H8 reached 499.1 percent, 469.0 percent if using SSSF; and reached 459.7 percent; 12659.2 percent, 1872.8 percent, and 6718.2 percent, respectively, compared with SF. Likewise, the average improvement of FPA, CMC-Na, and AVI of Q1 grew up by 805.6 percent, 434.4 percent, and 708.0 percent, compared with SSF if adopting SSSF; and increased by 1791.2 percent, 1382.5 percent, and 558.7 percent, respectively, compared with SF. So to fermentation for producing cellulase, the SSSF has more advantages over traditional SSF and SF. ③　In the SSSF, the recovery rate of extract of H81 and H82 were 14.9 percent, 18.3 percent, which increased by 26.3 percent, 63.4 percent than that of SSF, respectively. Similarly, the recovery rate of extract of Q11 and Q12 were 15.4 percent, 14.4 percent, which increasd by 30.5 percent and 28.6 percent, compared with SSF. Therefore, in contrast with the SSF, more cellulase with higher activity can be obtained from the SSSF. 3. Mixed culture can improve cellulase activity effectively. ①In the SSSF, the FPA, CMC-Na, and AVI of H8 and yeast in mixed culture improved averagely by 3.4 percent, 20.1 percent, and 42.0 percent than that in single culture; and the FPA, CMC-Na, and AVI of Q1 and yeast in mixed culture increased by 16.7 percent, 3.9 percent, and 5.8 percent, respectively, compared with single culture. ②In the SSF, the FPA, CMC-Na, and AVI of H8 and yeast in mixed culture improved averagely by 14.2 percent, 19.8 percent, and 30.1 percent than that of single culture; similarly, the FPA, CMC-Na, and AVI of Q1 and yeast in mixed culture increased averagely by 69.0 percent, 17.9 percent, and 1.4 percent, respectively, compared with single culture. ③In the SF, the FPA, CMC-Na, and AVI of H8 and yeast in mixed culture rised averagely by 40.6 percent, 27.0 percent, and 134.0 percent; and that of Q1 and yeast in mixed culture were up averagely by 26.1 percent, 67.2 percent, and 3.2 percent, respectively. 4. Making a comparison between organic nitrogen sources and inorganic nitrogen sources, the microorganism absorbs and utilizes the organic nitrogen more effectively than the inorganic nitrogen. Through SSF, we found that the cellulase activity of solid fermentation products adding organic nitrogen sources in the medium was higher than that of adding inorganic sources. To Q1, the oil residue and its acid hydrolysis can be used in fungi fermentation as a better organic nitrogen sources. To H8, dried blood and its hydrolysis are both better organic nitrogen sources. The acid hydrolysis of three kinds of organic nitrogen sources can not improve the enzymatic activity significantly so that we can add directly these nitrogen sources to the medium, and do not need to hydrolyse them。...