Biologically pretreated sugarcane top as a potential raw material for the enhancement of gaseous energy recovery by two stage biohythane process

[Display omitted] •Biological pretreatment showed 60.4% lignin removal from the sugarcane top.•Confocal microscopic and FTIR analysis confirmed lignin reduction.•Biohythane production enhanced the gaseous energy recovery up to 37.7%.•Unstructured model was used to determine the kinetics of product formation.•Material balance analysis showed the feasibility of the process. The aim of the present study was to develop a suitable pretreatment method to enhance the microbial degradation of lignocellulosic biomass and to maximize the overall energy recovery by using biohythane process. An efficient and eco-friendly biological pretreatment was used. Maximum lignin removal using biological pretreatment of sugarcane top was 60.4% w/w after 21d incubation at 28°C in static condition. Confocal microscopy observation and FTIR analysis confirmed the removal of lignin from sugarcane top. The maximum hydrogen production rate (Rm), hydrogen production potential (P) and lag time (λ) using pretreated sugarcane top were 16.76mL/g-VS/h, 87.40mL/g-VS and 3.38h respectively. The maximum methane production potential using spent medium of dark fermentation was 180.86mL/g-VS with the lag time of 2.9d. The overall gaseous energy recovery was 37.7% which is 54% higher than that of the untreated one.