**14.4 The effect of temperature**

The operating time was longer at low temperatures than that at high temperatures, but the voltage generation at high temperatures (30 and 35°C) was higher [100, 101]. The peak current and voltage intensity was measured at 35°C. Decreasing voltage, output and current intensity may occur for a variety of reasons. As temperature rises, the biochemical reactions, bacterial metabolism, and bacterial growth rate increases, leading to rapid bacterial growth and better voltage efficiency. Nonetheless, during long processing periods while bacteria are at high temperatures, essential cell's compounds like nucleic acid and other temperaturesensitive material can be irreversibly impaired, resulting in extreme cell function degradation or death. The voltage and current strength decrease drastically in this case. The slow bacterial growth rate at low temperatures often leads to a reduction in the bacterial population and activity and voltage output decreases [102].
