Hydrolysis Lab Report

2.4.1 Hydrolysis
In the first stage, complex organic compounds (such as carbohydrates, fats and proteins) are hydrolyzed, resulting in simpler compound (simple sugars like glucose) through enzymes produced by fermentive bacteria. In an anaerobic digestion process where organic polymers form a substantial portion of the waste stream to be treated, the hydrolyzing bacteria and their enzymes are of paramount importance because their activity produces the simpler substrates for the succeeding steps in the degradation sequence. The most common extra cellular hydrolytic enzymes are lipases, proteases, amylases and cellulases, which are excreted by hydrolytic bacteria (Zeikus 1980). Other extra cellular enzymes which may participate in the initial hydrolysis step of anaerobic digestion are the pectinolytic enzymes such as those elaborated by some Bacillus and Clostridium species, and the dextranases of, for example, Bacillus species.
In sewage sludge, hydrolytic bacterial populations are usually high and generally comprise between 108 and 1010 bacteria per mL of sludge (Hobson et al 1974). The general hydrolysis equation is shown in Equation (2.1). C6H10O4 + 2H20 C6H12O6 + H2

In general, the hydrolysis step can be considered as the rate-limiting step for anaerobic digestion (Pavlostatis and Giraldo-Gomez 1991). During the treatment of dairy and slaughterhouse wastewater the rate limiting step is the hydrolysis of particulate substrates (Pavlostatis and Giraldo-Gomez 1991 and Nunez and Martinez 1999). In the treatment of pig slaughterhouse effluent hydrolysis of proteins appears to be rate limiting step (Batstone et al 2000). Proteins are degraded slower than carbohydrates and lipids under acidogenic conditions (Elefsiniotis and Oldham