Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman Hybridization of sugar-carboxylate-syngas platforms for the production of bio-alcohols from lignocellulosic biomass (LCB) – A state-of-the-art review and recommendations Ranjana Chowdhury a, ⁎ , Shiladitya Ghosh a , Dinabandhu Manna a , Sumona Das a , Sambit Dutta a , Sabine Kleinsteuber b , Heike Sträuber b , Md. Kamrul Hassan c , Suvi Kuittinen c , Ari Pappinen c a Chemical Engineering Department, Jadavpur University, Kolkata 700032, India b Department of Environmental Microbiology, UFZ – Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany c School of Forest Sciences, University of Eastern Finland, P.O. Box 111, 80101, Finland ARTICLE INFO Keywords: Bioalcohol Lignocellulosic Biomass Sugar-carboxylate-syngas platforms Hybridization Challenges Recommendations ABSTRACT Lignocellulosic biomass (LCB), the most abundant renewable feedstock for bioenergy generation, is commonly converted to second generation bioalcohols, the main drop-in fuels for petroleum gasoline, through three technologies based on sugar, carboxylic acid and syngas platforms. The hybridization of either any two or three platforms altogether is a novel concept aimed at improvement of yield and quality (high heating value) of bioalcohols. This article reviews the present status of the integration techniques of hybrid platforms with an overall assessment of their advancement with respect to their individual counterpart as well as the challenges involved. It has been indicated that to extract the maximum benefit of hybridization, research studies should be spurred in the fields of kinetic analysis of all thermochemical and biochemical processes, microbial interaction, optimization of process parameters (pH, temperature), performance analysis of engine for the utilization of mixed product bioalcohols, sustainability analysis through the development of mathematical models for lab- scale operations and process simulation models for large scale units along with life cycle assessment. Moreover, pyrolysis of LCB has been identified as a unique central process for the supply of all intermediate compounds, namely, sugar, carboxylic acid and syngas during the hybrid networking of three platform technologies. In this context, the scheme of CONVER-B, a joint research project under the INNO-INDIGO partnership program, aiming at sustainable integration of the platforms to produce bio-alcohols from LCBs leaving zero effluent simulta- neously with carbon sequestration potential has been introduced and discussed. 1. Introduction Lignocellulosic biomass (LCB) derived biofuels and bioproducts are the key driver in the path of transition towards the bio-based economy all over the world, establishing absolute alliance among energy, society and environment [1,2]. It is well established that bioenergy, one of the preeminent components of bio-economy, will be mainly dependent on LCB as the chief renewable resource (feedstocks), mostly due to their worldwide abundance [1,3]. Being the most abundant feedstock ap- pearing as residues of agriculture, forestry and as effluents from food, textile, pulping and other industrial processing, LCB could be used in biorefineries to generate myriads of renewable bioproducts; biofuels being the supreme product [4–7]. One of the advantages of using LCB as feedstock for bioenergy generation is that it totally eliminates the up- setting social issue of ‘food vs. fuel’ competition [4,8]. Conventionally, lignocellulosic wastes are converted to biofuels (gaseous: biogas/bio- methane; biohydrogen; bio-syngas and liquid: bio-alcohols and bio-oil) either through biochemical or thermochemical routes [9–14]. As re- ported in the latest survey by the International Energy Agency (IEA), conventional biofuel production reached 143 billion litres (4% incre- ment on a year-on-year basis), in the year 2017, having an equivalent energy value of 83 Mtoe [15]. Analyzing the ongoing trend of world biofuel production, IEA forecasted a 15% growth estimating to be 165 billion litres (total energy value 97 Mtoe) by 2023, 119 billion li- tres (approximately two-third) of which will come from bioethanol alone [15]. This fact is already being implemented globally and is https://doi.org/10.1016/j.enconman.2019.112111 Received 10 June 2019; Received in revised form 27 August 2019; Accepted 28 August 2019 ⁎ Corresponding author. E-mail addresses: ranjana.juchem@gmail.com (R. Chowdhury), sabine.kleinsteuber@ufz.de (S. Kleinsteuber), heike.straeuber@ufz.de (H. Sträuber), kamrul.hassan@uef.fi (Md. Kamrul Hassan), suvi.kuittinen@uef.fi (S. Kuittinen), ari.pappinen@uef.fi (A. Pappinen). Energy Conversion and Management 200 (2019) 112111 Available online 29 September 2019 0196-8904/ © 2019 Elsevier Ltd. All rights reserved. T