Enzymatic activity and microbial biomass in soil amended with biofuel production byproducts

► Recycling biofuel byproducts to soil can be a possible method of their disposal. ► Biofuel byproducts contain essential plant nutrient and might be used as organic amendment/fertilizer. ► Effect of biofuel byproducts application to soil on microbial activity was evident. ► Biofuel byproducts application to soil did not show a negative impact on biological indicators of soil quality.