Enter the unconventional Horten brothers, who were at work on one such weapon. Lead designer Reimar Horten was a glider designer obsessed with the all wing design because of the possibilities it created for low drag and exceptional performance, said Florida based aviation historian David Myhra, who interviewed the Horten pair numerous times from the early 1. Efficient evaluation of cellulose digestibility by. Trichoderma reesei. Rut C3. 0 cultures in online monitored shake flasks. Effects of glucose and glycerol on the respiration activity of T. Rut C3. 0The production of cellulases is strongly influenced by the applied carbon source. If cellulose, a strong natural inducer of cellulase production, is used as sole carbon source, the initial spore germination will be strongly delayed. Therefore, complex compounds like peptone or yeast extract are often included in the culture broth to initiate growth 1. However, to avoid the influence of lot to lot variations of complex compounds during process characterization, their use should if possible be avoided 2. Instead, two different carbon sources, namely glycerol and glucose, were tested to minimize the lag phase of the cultivation. Although glucose is a repressor for the production of cellulases, it is often included in pre culture media 1. In contrast, glycerol does not influence the production of cellulases 1. To monitor the growth in shake flasks in presence of a solid substrate, the respiration activity monitoring system RAMOS was used. Figure 2a shows the oxygen transfer rate OTR and cumulative oxygen transfer OT over time of a T. Rut C3. L1 as sole carbon source and cellulose in combination with glucose 5. L1 or glycerol 5. L1. The amount of different carbon sources was adapted to yield the same overall amount of carbon. The measurements were performed in duplicates and the low variations prove the excellent repeatability of the cultivation in one parallel experiment. This is especially remarkable, as T. However, it has already been shown that T. The reproducibility of experiments performed at different time points is lower and is shown in the Additional file 1 Figure S1. Due to the detected intrinsic variability of the biological system, comparison of different cultivation conditions was always performed using only data from parallel experiments. Fig. 2. Effects of glucose and glycerol on the respiration activity of T. Rut C3. 0. T. reesei Rut C3. L1 and cellulose 3. L1 in combination with glucose 5. L1 or glycerol 5. L1. All cultures contained the same molar amount of carbon. Duplicates of oxygen transfer rate OTR and cumulative oxygen transfer OT. For clarity only every second measuring point over time is represented by a symbol b cellulose and protein content in the culture supernatant c p. H and filter paper activity FPA. Error bars represent standard deviation of technical triplicates. Culture conditions modified Pakula medium, 2. L flask, filling volume 2. L, shaking frequency 3. L1, and 3. 0 CThe culture containing cellulose as sole carbon source has the longest lag phase of about 4. Afterwards, the OTR increases to a maximum of 1. L1 h1 after 7. 0 h and then decreases very slowly over a period of 34 days in the further course of the cultivation. High cellulose consumption Fig. H Fig. 2c coincide with the increase in OTR. In contrast, low cellulose consumption and a decelerated decline in p. H can be observed during the subsequent OTR decrease after 7. In comparison, a culture supplemented with glycerol has a slightly shorter lag phase, but reaches the same maximum OTR at a similar time point. The maximum is followed by a short instantaneous drop and an increase in OTR reaching a second maximum of about 1. L1 h1 after 8. 0 h. This is a characteristic course of OTR for diauxic growth on two carbon sources 3. The analysis of cumulative oxygen transfer OT and the course of cellulose consumption reveal that cellulose and glycerol are consumed simultaneously. The drop in OTR at about 7. The rate of final OTR decrease is similar to that of the culture with solely cellulose. The culture containing glucose has the shortest lag phase and reaches its first maximum of 1. L1 h1 after 2. 8, 4. Furthermore, a similar two peak pattern as with glycerol is observed except for a steeper OTR decrease between the two maxima reaching a minimum of 3 mmol L1 h1. HPLC analysis confirms glucose is depleted at this local minimum data not shown. Figure 2b illustrates that the consumption of cellulose in the culture with glucose, which is indicated by the second increase in OTR, does not set in until the initial glucose is consumed. Nonetheless, cellulose consumption starts about 1. The OT of all three cultures reaches a final value of around 6. L1, indicating that the same amount of carbon was taken up. This is confirmed by the fact that the remaining cellulose concentration is around 4 g L1 in all cultures. Additionally, the same final p. H value of roughly 3. The main proteins secreted by T. Rut C3. 0 are cellulases. Therefore, the extracellular protein content correlates with the amount of cellulases produced 3. As shown in Fig. 2b, a total protein concentration Bradford between 1. L1 were reached in all cultures at the end of the fermentation. The final cellulase activity measured by the filter paper activity assay was around 0. FPU m. L1 for all cultures, the culture with glycerol reaching slightly higher values Fig. The comparison of all three cultures reveals that the lag phase can be significantly shortened by addition of glucose, which is in good agreement with Zhang et al. The addition of glycerol influences the lag phase only slightly. It has to be noted that cellulose and glycerol were consumed simultaneously in contrast to glucose and cellulose, which were taken up consecutively. The reason for this might be the repressing effect of glucose on cellulase production 1. No significant influence of glucose on the quantity of enzymes produced by T. Rut C3. 0 was detected, however, enzyme production started at an earlier time point. Outbreak Zombie Game Simulator Ps4. This might be due to the fact that the addition of glucose results in a higher biomass formation allowing a faster cellulase production after the depletion of glucose. This assumption is supported by the earlier second rise in OTR starting at about 3. Szijarto et al. 3. He suggested to perform two stage cultivations, first on glucose for biomass formation, and afterwards using cellulose for enzyme production. The results obtained in this study suggest that via glucose addition to a culture containing cellulose, biomass growth and enzyme production can be realized in a single stage. Therefore, further experiments were performed using both glucose and cellulose as carbon sources to achieve a faster initiation of cellulose consumption. Digestibility of different commercial celluloses. The physical properties of the utilized celluloses influence induction of cellulase production as well as the rate of hydrolysis, thus determining their biological digestion rate 1. To evaluate the influence of cellulose with different physicochemical properties on the respiration activity of T. Rut C3. 0, four commercially available celluloses, namely cellulose, Sigmacell 1. Sigmacell 2. 0, and Sigmacell 5. Their crystallinity as well as particle size are given in Table. All cultures contained 5 g L1 glucose and 3. L1 cellulose. Figure 3a depicts the course of OTR over time. As expected, the observed pattern for the culture containing glucose and cellulose is very similar compared to the results shown in Fig. Regardless of the type of cellulose the OTR profiles exhibit a two peak pattern. The first maximum of 1. L1 h1, corresponding to glucose consumption, is reached after 2. The second peak has a different shape depending on the type of cellulose investigated. The second increase in OTR for the culture on cellulose Crl 4. Sigmacell 1. 01 amorphous starts simultaneously. However, the maximum OTR reached on Sigmacell 1. The OTR maximum further decreases for Sigmacell 2. Crl 5. 2. 6 and Sigmacell 5. Crl 5. 6. 1 to about 8 and 7 mmol L1 h1, respectively.