The present disclosure is generally directed to process of gasification of carbonaceous materials to produce synthesis gas or syngas. The present disclosure provides improved methods of gasification comprising: adding one or more carbonaceous materials, adding a molecular oxygen-containing gas, adding a methane-containing gas and optionally adding water or steam into said gasifier. This disclosure is also directed to process of production of one or more alcohols from said syngas via fermentation or digestion in the presence of at least one microorganism.