A Simplified Techno-Economic Analysis for Sophorolipid Production in a Solid-State Fermentation Process

Abstract

Sophorolipids (SLs) are microbial biosurfactants with an important role in industry and a continuously growing market. This research addresses the use of sustainable resources as feedstock for bioproducts. Winterization oil cake (WOC) and molasses are suitable substrates for SLs via solid-state fermentation (SSF). The model proposed herein was established for annually processing 750 t of WOC and comparing three support materials: wheat straw (WS), rice husk (RH), and coconut fiber (CF). Production capacity ranged 325–414 t of SLs per year. Unit Production Cost was 5.1, 5.7, and 6.9 USD/kg SL for WS, RH, and CF production models, respectively, and was slightly lower with other substrates. Financial parameters were CAPEX 6.7 MM USD and OPEX 1.9 MM USD/y, with a NPV, IRR and payback time of 6.4 MM USD, 31% and 3.2 y, respectively. SLs recovery from the solid matrix was the major contributor to operating costs, while fermentation equipment shaped capital costs. Results show that the physical properties (bulk density, WHC) of substrates and supports define process costs beyond substrate purchase costs and process yields in SSF systems. To our knowledge, this is the first attempt to model SLs production via SSF at full scale for the economic valuation of the SSF process.

Sustainable biosurfactant production from secondary feedstock—recent advances, process optimization and perspectives

“…Additionally, SL production was deemed more sustainable, as the purification of lactic acid and succinic acid required more complex downstream processes, consuming greater energy and chemicals. When producing SL via solid-state fermentation (SSF) using winterization oil cake (WOC) and molasses as secondary feedstocks, the physical properties of substrates and supports, such as bulk density and water-holding capacity, play a crucial role in determining process costs beyond the expenses incurred for substrate purchase and process yields (Martinez et al, 2022). In production processes, electricity costs constitute a significant proportion of variable costs, reaching as high as 78.22% (Moutinho et al, 2021).…”

Carbon and nitrogen optimization in solid-state fermentation for sustainable sophorolipid production using industrial waste

“…Consequently, impurities can be present in the final crude product, affecting the downstream process design and overall economic performance. Martínez et al (2022) described SL recovery from the solid matrix as the major contributor to operating costs.…”

“…The utilization of alternative substrates such as food waste, green residues, and industrial organic waste has positioned SL production within the context of a green bioeconomy, Glucose* (g L -1 or g kg -1 ) TC* (g L -1 or g kg -1 ) TN* (g L -1 or g kg -1 ) Frontiers in Bioengineering and Biotechnology frontiersin.org with a global biosurfactant market of over 5.52 billion by 2022, with an increasing rate of 5.5% per year (Markets and Markets, 2016;Singh et al, 2019). Due to the high interest generated around this topic, several techno-economic evaluations have been developed for biorefineries and scaled-up processes using alternative feedstocks (Wang et al, 2020;Martínez et al, 2022). As reported in the literature, glucose has been recognized as the principal hydrophilic carbon source utilized in SL industrial production.…”

Solid-State Fermentation from Organic Wastes: A New Generation of Bioproducts

“…Starmerella bombicola [29] SSF of brewers' spent grain, after two pretreatments: extrusion and blade milling.…”

“…They are classified into trehalolipids, mannosylerythritol lipids (MEL), rhamnolipids, and sophorolipids (SL) [42]. Among them, SL, which consist of a hydrophobic fatty acid tail of 16 or 18 carbon atoms and a hydrophilic carbohydrate head sophorose, have been recently reported as biosurfactants that can be produced using SSF in several conditions and in a viable economic way [29], and they are even supplied by several companies, although normally produced by SmF. The use of SL is increasing according to the literature, where the yeast Starmerella bombicola is the main reported producer [43].…”