Biogas or natural gas or methane produced from farm/agro/crop/domestic waste can also be used for producing protein rich feed for cattle/fish/poultry/pet animals economically by cultivating "Methylococcus capsulatus" bacteria culture in a decentralised manner near to the rural / consumption areas with tiny land and water foot print. With the availability of CO2 gas as by product from these units, cheaper production cost of algae oil from algae or spirulina particularly in tropical countries like India would displace the prime position of crude oil in near future.