Evaluating the economic viability and environmental impact of emerging technologies is crucial for the transition to a bio-based economy. This study proposes a methodology to assess the environmental and economic performance of bio-based lactic acid (LA) production by scaling up from pilot to industrial levels using fiber sludge, a residue from the pulp and paper industry, as a feedstock. Process design, Techno-Economic Analysis (TEA) and Life Cycle Assessment (LCA) were conducted at pilot scale to identify key environmental and economic hotspots. External costs were estimated following the environmental Life Cycle Costing (eLCC) approach using the Environmental Prices (EP) method. At the pilot scale, the LCA indicated a Global Warming Potential (GWP) of 3.87 kg CO₂-eq, which aligns with the values reported in previous studies. Scaling up to different plant capacities revealed the potential economies of scale. At a production rate of 50 kt per year, the Minimum Selling Price (MSP) was estimated at 1.71€/kg, which is comparable to that of other bio-based LA production routes. Assuming proportional environmental impacts from pilot to industrial scale, external costs were integrated into the MSP, resulting in adjusted values of 2.04€/kg (lower value), 2.21€/kg (central value), and 2.46 €/kg (upper value). Sensitivity and uncertainty analyses using Monte Carlo simulations indicated an 87.5 % probability of achieving a positive Net Present Value (NPV). This study highlights the need for standardised methodologies to evaluate the environmental and economic impacts of emerging bio-based technologies, particularly when accounting for external costs

The effective and cheap production of platform chemicals is a crucial step towards the transition to a bio-based economy. In this work, biotechnological methods using sustainable, cheap, and readily available raw materials bring bio-economy and industrial microbiology together: Microbial production of two platform chemicals is demonstrated [lactic (LA) and succinic acid (SA)] from a non-expensive side stream of pulp and paper industry (fibre sludge) proposing a sustainable way to valorize it towards economically important monomers for bioplastics formation. This work showed a promising new route for their microbial production which can pave the way for new market expectations within the circular economy principles. Fibre sludge was enzymatically hydrolysed for 72 h to generate a glucose rich hydrolysate (100 g·L−1 glucose content) to serve as fermentation medium for Bacillus coagulans A 541, A162 strains and Actinobacillus succinogenis B1, as well as Basfia succiniciproducens B2. All microorganisms were investigated in batch fermentations, showing the ability to produce either lactic or succinic acid, respectively. The highest yield and productivities for lactic production were 0.99 g·g−1 and 3.75 g·L−1·h−1 whereas the succinic acid production stabilized at 0.77 g·g−1 and 1.16 g·L−1·h−1. Copyright © 2023 Olszewska-Widdrat, Xiros, Wallenius, Schneider, Rios da Costa Pereira and Venus.