This work illustrates the co-composting of gelatin industry sludge (GIS) combined with organic fraction of municipal solid waste (OFMSW) and poultry waste (PW) employing 10% zeolite mixed with enriched nitrifying bacteria consortium (ENBC). Five piles of GIS were prepared mixed with OFMSW and PW at 2:1:0.5, 4:1:0.5, 6:1:0.5 and 8:1:0.5 and without GIS 0:1:0.5 (dry weight basis) served as control, while 10% zeolite mixed with ENBC was inoculated in all piles and composted for 42 days. The Pile-4 with GIS, OFMSW and PW ratio 6:1:0.5 and 10% zeolite + ENBC were drastically reduced the nitrogen loss and enhance the mineralization rate as compare to other piles. The co-amendment of 6% GIS effectively buffered the pH between similar to 7.5 to 8.0 and shortened the compost maturity period, while lower concentration of GIS was comparatively delayed the early decomposition. Therefore, our results suggested that suitability of 10% zeolite + ENBC with initial feedstock ratio 6:1:0.5 as the best formulation for the composting of GIS into value-added stable product. (C) 2016 Elsevier Ltd. All rights reserved.