Adelekan (2011) produced methane from cocoyam corms and related the volumes and masses obtained to the masses of corms used; derived guiding numerical relationships for the processes and extrapolated these values using production quantities of the crop reported globally and finally submitted workable estimates as regards biogas which is derivable from aggregate global production of the crop. The scientific innovation and relevance of the work reported lies in the fact that the fermentation and anaerobic digestion methods used are applicable across countries and regions irrespective of available degree of industrialization and climate. A new vista is opened in the use of this neglected crop as a cheap renewable source of energy in view of the rapid depletion, environmental pollution and high costs of fossil fuels. Results show that the 10 million tonnes annual global production of cocoyam is potentially able to produce 39.5 million cubic metres of methane which on burning would produce 179.3 x 107 MJ of enerrgy. The mash obtained as byproduct of the processes is capable of supplying 59 calories of food energy per 100g which is an excellent feedstock for livestock. The use of cocoyam (Colocasia and Xanthosoma species) as a renewable source of energy for the production of biogas poses no threat to the environment or food supply and is therefore recommended. Furthermore, doing so helps to enhance energy security.

Adeyosoye et al., (2010) studied biogas yield of peels of sweet potato (SPP) and wild cocoyam (WCP). Buffered and sieved goat’s rumen liquor was added to 200 mg of dried and milled SPP and WCP in 100 ml syringes supplied with CO2 under anaerobic condition and incubated for 24 hr. Total biogas produced was measured at 3 hr intervals till the 24th hr when the fermentation was terminated. The inoculum was also incubated separately. The proximate composition of SPP and WCP were similar except for the higher EE content (12%) of SPP. The SPP and WCP used contained 26.81 and 26.97% DM, 3.06 and 3.83% CP, and 78.94 and 79.17% carbohydrate respectively. Both samples had the same crude fibre (7.00%) content. Total biogas produced from SPP, WCP and the inoculum varied from 13.0, 11.0 and

5.0 ml respectively at the 3rd hr through 66.5, 61.5 and 18.0 ml at the 18th hr to 77.5, 72.0 and

30.0 ml at the 24th hr respectively. The differences in biogas production across the treatments were significant (p < 0.05). There were no significant differences (p > 0.05) in the volumes of methane produced from SPP (42.5 ml) and WCP (39.5 ml) which were significantly (p < 0.05) higher than 20.0 ml produced by the inoculum. The study pointed out that peels of sweet potato and cocoyam wastes can produce significant quantities of biogas for domestic applications. The foregoing studies confirm that ultimate methane yields from biomass are influenced principally by the biodegradability of the organic components. The more putrescible the biomass, the higher is the gas yield from the system (Wis, 2009).