Microbial degradation temperature effect

The sol-gel procedure enables encapsulation of enzymes in optically transparent, porous silicate matrices, under mild room-temperature conditions. The small pores prevent microbial degradation and, due to the biomolecule size, they will not diffuse out of the polymer network. The physical encapsulation avoids self-aggregation effects as well as protein unfolding and denaturalization. At the same time, the catalytic activity is maintained as the enzymes are able to react with small substrates that can transfer across or within the support, assuring continuous transformations [75]. 

Climate changes may also have significant effects on lake DOC concentrations. In a 20-year study of boreal lakes in the Experimental Lakes Area of northwestern Ontario, Schindler et al. (1997) reported that lake DOC concentrations declined by 15-25% as mean annual temperatures increased by 1.6°C, precipitation declined by 40%, and runoff declined by 70% due to increased evaporation and decreased precipitation. The primary reason for the decline in lake DOC was reduced inputs of DOC from terrestrial catchments, although in-lake removal of DOC also increased slightly via either increased acidification, UV light penetration, or microbial degradation. 

Temperature and moisture are two of the most important environmental variables that affect microbial growth, survival, and activity. At optimal temperature and moisture conditions, chemical and enzymatic reactions in the cell will occur the most rapidly and growth and activity will be the highest. However, below and above these optimal conditions, microbial activity decreases. The microbial degradation of. v-triazines appears to follow the same pattern. The effect of soil moisture and temperature on the degradation of terbutryn was evaluated by Chu-Huang et al. (1975). They reported that after 20 weeks of incubation above 10°C and at 14% soil moisture, phytotoxic levels of terbutryn to wheat were not detected in Teller sandy loam soil. 

The latter is because laboratory data are typically obtained with specific and well-characterized microorganisms, while the real world provides all kinds of microorganisms, not necessarily including those employed in the laboratory. Laboratory data demonstrate general regularities of microbial degradation, such as effect of temperature, nutrients, pH, effect of antimicrobial agents, and so on. Each one of these factors can be very different in the real world. 

Physical-chemical ambient conditions have a very strong effect on microbial degradation, Figure 5.374. Subsequent biodegradation can be positively influenced by increasing the polymer surface accessible to microbial attack via biotic hydrolysis (pH-value, water content) or physical disintegration (temperature, mechanical reduction) [928]. 

CDU in pure form is a white powder. It is made slowly available to the soil solution by nature of its limited solubihty in water. Once in the soil solution, nitrogen from CDU is made available to the plant through a combination of hydrolysis and microbial decomposition. As with any CRE which is dependent on microbial action, the mineralization of CDU is temperature dependent. Product particle size has a significant effect on CDU nitrogen release rate. Smaller particles mineralize more rapidly because of the larger surface contact with the soil solution and the microbial environment. The rate of nitrogen release is also affected by pH because CDU degrades more rapidly in acidic soils. 

S.L. Trabue, T.M. Crowe, and J.H. Massey, Changes in soil biomass and microbial community structure as affected by storage temperature and duration effect on the degradation of metsul-furon methyl in Pesticide Environmental Eate Bridging the Gap Between Laboratory and Eield Studies , ed. W. Phelps, K. Winton, and W.R. Effland, ACS Symposium Series 813, American Chemical Society, Washington, DC (2002). 

---