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[Display omitted] • LCA study of fermentative production of succinic acid using bread waste. • GHG emissions and non-renewable energy use (NREU) are evaluated. • Processes using steam and heating oil are found to be environmental hotspots. • GHG emissions and NREU were significantly lower than fossil based succinic acid. According to the US Department of Energy, succinic acid (SA) is a top platform chemical that can be produced from biomass. Bread waste, which has high starch content, is the second most wasted food in the UK and can serve as a potential low cost feedstock for the production of SA. This work evaluates the environmental performance of a proposed biorefinery concept for SA production by fermentation of waste bread using a cradle-to-factory gate life cycle assessment approach. The performance was assessed in terms of greenhouse gas (GHG) emissions and non-renewable energy use (NREU). Waste bread fermentation demonstrated a better environmental profile compared to the fossil-based system, however, GHG emissions were about 50 % higher as compared to processes using other biomass feedstocks such as corn wet mill or sorghum grains. NREU for fermentative SA production using waste bread was significantly lower (~ 46 %) than fossil-based system and about the same as that of established biomass-based processes, thus proving the great potential of waste bread as a valuable feedstock for bioproduction of useful chemicals. The results show that steam and heating oil used in the process were the biggest contributors to the NREU and GHG emissions. Sensitivity analyses highlighted the importance of the solid biomass waste generated in the process which can potentially be used as fish feed. The LCA analysis can be used for targeted optimization of SA production from bread waste, thereby enabling the utilization of an otherwise waste stream and leading to the establishment of a circular economy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lactic acid (LA) produced from pure/crude xylose under non-sterile conditions. • Crude xylose obtained from sugarcane bagasse (SCB) and olive pits (OP). • 97.8 g/L LA accumulated with 0.67 g/g yield on pure xylose. • 52–62 g/L LA titres attained with 0.50–0.60 g/g yield from SCB/OP hydrolysates. • Recovery of 80–90% LA demonstrated using aqueous two-phase system. Lactic acid (LA) is a platform chemical with diverse industrial applications. Presently, commercial production of LA is dominated by microbial fermentation using sugary or starch-based feedstocks. Research pursuits emphasizing towards sustainable production of LA using non-edible and renewable feedstocks have accelerated the use of lignocellulosic biomass (LCB). The present study focuses on the valorisation of xylose derived from sugarcane bagasse (SCB) and olive pits (OP) through hydrothermal and dilute acid pretreatment, respectively. The xylose-rich hydrolysate obtained was used for LA production by homo-fermentative and thermophilic Bacillus coagulans DSM2314 strain under non-sterile conditions. The fed-batch mode of fermentation resulted in maximum LA titers of 97.8, 52.4 and 61.3 g/L with a yield of 0.77, 0.66 and 0.71 g/g using pure xylose, xylose-rich SCB and OP hydrolysates, respectively. Further, a two-step aqueous two-phase system (ATPS) extraction technique was employed for the separation and recovery of LA accumulated on pure and crude xylose. The LA recovery was 45 – 65% in the first step and enhanced to 80–90% in the second step.The study demonstrated an efficient integrated biorefinery approach to valorising the xylose-rich stream for cost-effective LA production and recovery. [ABSTRACT FROM AUTHOR]