## 11 Multifunctionality of the Newly Characterized Processive Endocellases
[169] showed that endocllulases, exocellulases and xyloglucanases together could exert considerable synergy in degradation of raw plant cell wall materials. Thus, these novel GH5-tCelSA1 and GH5-p4818 Cel5_2A endocellulases with unique multi-functional hemicellulose activities of hydrolyzing crystalline celluloses and hemicelluloses will have an excellent potential as an exogenous feed enzyme additive for livestock feeding and as a highly efficient biocatalyst to enable competitive lignocellulosic ethanol production. Further laboratory scale of tests and field experiments need to be conducted to examine the efficacy of these novel GH5-tCel5A1 and GH5-p4818 Cel5_2A endocellulases in hydrolysis of livestock feed and biofuel feedstock samples. Optimal Biochemical and Physiological Properties of the Newly Characterized Processive Endocellulases  
These novel GH5-tCel5A1 and GH5-p4818 Cel5_2A endocellulases had pH optimum in a light acidic to neutral pH environment of 5.0-7.0 with the majority (about 60%) of its activity retained for a wide range of pH, ranging from very acidic pH of 4 to alkaline pH of 8.5 (Table 1) [45; 127]. These results were consistent with the pH optimum and effects of pH on endocellulase activity response patterns previously reported in three novel GH5 cellulases screened and characterized out of bovine rumen metagenomes [54; 55; 157] and rabbit eccum [56]. These GH5 endocellulase pH optimum and effects of pH on the endocellulase activities would reflect adaptive evolution of these endocellulases and their host bacteria to the ruminal, gastric, small and large intestinal luminal pH environment and the more alkaline pH environment in the middle and the distal regions of the small intestine in porcine, monogastric herbivore and bovine species. The light acidic to neutral pH optimum at 6-7 and the tolerance to a wide range pH environment for these novel GH5-tCel5A1 and GH5-p4818 Cel5_2A are valuable biochemical properties which enable its potential wide range of industrial applications as an exogenous feed enzyme additive, saccharification of feedstock for production of lignocellulosic ethanol as well as a number of other applications in light industries such as textile, detergent, food processing and wood and paper pulp polishing. The GH5-p4818 Cel5_2A endocellulae had optimal temperature at 50 \({}^{\circ}\)C with majority (above 75%) of its endocellulae activity retained between 37 and 50 \({}^{\circ}\)C, which represented a marginal overlap between mesophilic (20-45 \({}^{\circ}\)C) and thermophilic (50-75 \({}^{\circ}\)C) temperature zones, whereas Ccel5A1 endocellulae activity was shown as optimal at the thermophilic (50-75 \({}^{\circ}\)C) temperature zone [45, 127]. [PERSON] et al. [56] reported several novel cellulases with optimal temperature between 40 and 55 \({}^{\circ}\)C screened and characterized out of rabbit cecal metagenome. [PERSON] et al. [54] reported a novel GH5 cellulase with an optimal temperature at 60 \({}^{\circ}\)C screened and characterized out of yak rumen metagenome, and [PERSON] et al. [55] reported a novel GH5 cellulase with an optimal temperature at 50 \({}^{\circ}\)C screened and characterized out of buffalo rumen metagenome. It is known that normal mammalian body core temperature is at about 37 \({}^{\circ}\)C and ruminal digesta core temperature is at about 39 \({}^{\circ}\)C [54]. The mesophilic forest soil bacterium _Clostridium Phytofermantas_ GH9 processe endocillusae was a thermophilic enzyme with an optimal temperature at 65 \({}^{\circ}\)C [78]. Horizontal gene transfer might have played a role for the discrepancy of the optimal temperatures and the inhabiting environment temperatures among these endocillulases to which the aforementioned hosting bacteria adapted.