Figure 1 . Heat capacity of samples as a function of temperature
Although there are no general statements on heat capacity changes, the heat capacity of the samples increased steadily with rise in temperature. The heat capacity shows a linear relationship with temperature over the range of (190 to 300) K as shown in equations (2), (3) and (4), respectively.
\(BA:\ C_{p}\left(\text{J.\ }K^{-1}g^{-1}\right)=0.2422+0.0028\ T\ \left(K\right)\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (2)\)
\(BCN:\ C_{p}\left(\text{J.\ }K^{-1}g^{-1}\right)=0.1889+0.0032\ T\ \left(K\right)\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (3)\)
\(GA:\ C_{p}\left(\text{J.\ }K^{-1}g^{-1}\right)=0.1845+0.0034\ T\ \left(K\right)\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (4)\)
The heat capacity of GA samples was shown to be the highest. The low heat capacity observed for BCN samples maybe due to the stress imposed by the free cyanide during microbial proliferation which in turn could affect the biomass structural integrity compared to GA samples. Furthermore, BA samples recorded the lowest heat capacity when compared with all other samples studied. This was expected since Beta vulgaris contains approximately 9.56 % carbohydrate that served as an energy and/or carbon source for the F. oxysporum used [34, 35]. The higher values of heat capacity in BCN samples when compared to BA samples, could be directly related to the microorganism’s ability to utilise cyanide as a carbon source to supplement carbohydrates in B. vulgaris agro-industrial waste. Since there is no other reports on heat capacities of microbial dried biomass in literature particularly for fungi, comparing the heat capacity of Fusarium oxysporum with Saccharomyces cerevisiae showed that from the results obtained, GA samples were comparatively similar to those reported by Battley [17].
Table 3 compares the values of specific heat capacities of starch and/or glucose samples reported by previous authors. At temperature range of (200 to 300) K, our result is closer to the Boerio-Goates report [14] especially GA sample. All the specific heat capacity reported by [17] were higher than our findings while [16] is lower than our reports for BCN and GA samples. Generally, our report can be seen within the reported heat capacity for starch in literature.
Table 3: Comparison of specific heat capacities (\(\text{J\ }K^{-1}g^{-1}\)) for organic samples