Landfill leachate enhances fermentative hydrogen production from glucose and sugarcane processing derivatives

Fermentation can use renewable raw materials as substrate, which makes it a sustainable method to obtain H 2 . This study evaluates H 2 production by a mixed culture from substrates such as glucose and derivatives from sugarcane processing (sucrose, molasses, and vinasse) combined with landfill leachate. The leachate alone was not a suitable substrate for biohydrogen production. However, leachate blended with glucose, sucrose, molasses, or vinasse increased the H 2 production rate by 2.0-, 2.8-, 4.6-, and 0.5-fold, respectively, as compared with the substrates without the leachate. Determination of metals (Cu, Cd, Pb, Hg, Ni, and Fe) at the beginning and at the end of the fermentative assays showed how they were consumed during the fermentation and demonstrated improved H 2 production. During fermentation, Cu, Fe, and Cd were the most consumed leachate metals. The best substrate combination to produce H 2 was molasses and leachate, which gave high volumetric productivity—469 ml H 2 /l h. However, addition of the leachate to the substrates stimulated lactic acid formation pathways, which lowered the H 2 yield. The use of leachate combined with sugarcane processing derivatives as substrates could add value to the leachate and reduce its polluting power, generating a clean energy source from renewable raw materials.