Use of Agro-Industrial Waste for Biosurfactant Production: A Comparative Study of Hemicellulosic Liquors from Corncobs and Sunflower Stalks

Abstract

Biosurfactants have attracted considerable attention because of their lower toxicity, biocompatibility, and effectiveness over chemical surfactants. The use of renewable sources and the concept of sustainable production for such biomolecules supports the increased demand for eco-friendly products. Herein, the present study investigated corncobs (CC) and sunflower stalks (SS) as substitutes for conventional substrates in submerged fermentation with B. subtilis. The agro-industrial residues were submitted to an alkaline pretreatment to obtain hydrolysates rich in hemicelluloses, whose concentrations were determined at 48.8% and 65.7% for corncob and sunflower stalk liquors, respectively. The influence of different concentrations of glucose (0, 2.5, and 5%) and liquor (0, 20%, and 40%) were evaluated according to cell concentration, surface tension reduction rate (STRR), and emulsification index (EI24). Biosurfactants obtained with the hemicellulose liquor of sunflower stalk showed the highest cell concentration (4.57 g/L) and STRR (58.07%), whereas the maximum values of EI24 (56.90% in hexane, 65.63% in toluene, and 64.86% in kerosene) were achieved by using corncob liquor. All top results were observed at 2.5% glucose, 20% liquor (CC or SS), and 1% mineral salts. Notably, excess glucose or liquor (CC or SS) negatively affected cell growth and biosurfactant performance. The results indicated the potential of corncobs and sunflower stalks as low-cost substrates to produce a high added-value biosurfactant with promising tensoative and emulsifying properties.

Advancements in biosurfactant production using agro-industrial waste for industrial and environmental applications

“…Industrial waste selection compromises the media content. There should be minimal pre-treatment and purification required of industrial waste feedstocks to decrease operating and capital expenses and the generation of obstacles like acetic acid ( Santos et al, 2023 ). Industrial waste primarily has three problems: pre-treatment, transportation costs, and raw material accessibility.…”

“…Using agricultural waste to produce useful biosurfactants is a sustainable and eco-friendly way to make use of organic wastes. The general stages in producing biosurfactants from agricultural waste are outlined here ( Santos et al, 2023 ). This approach uses agricultural waste materials as the substrate for the synthesis of biosurfactants, the schematic illustration of the biosynthetic strategies is shown in the Figure 4 .…”

Coconut Waste: Discovering Sustainable Approaches to Advance a Circular Economy

“…Hemicellulose is also a polysaccharide in the plant cell wall, but contrary to cellulose, its chain is highly branched and comprises diverse sugar units (pentose and hexoses) [79]. The main sugar units are xylose (the most representative component), glucose, and galactose, which are readily hydrolyzed by dilute acids and soluble in alkaline solutions [80,81]. Thus, hemicelluloses confer to the structure of the lignocellulosic biomass properties such as increased flexibility and a high fiber bonding area, which are essential when processing lignocellulosic materials and make it a desirable resource for applications in coatings and composite materials [82].…”

Comparative Study of Pretreatments on Coconut Fiber for Efficient Isolation of Lignocellulosic Fractions

“…Depending on the severity, it may also cause the de-crystallization of cellulose [24,25]. The alkaline solution acts by dissolving acetyl and uronic acid in hemicellulose and degrading ester and glycosidic side chains in lignin without degrading carbohydrates [26,27]. Schiavon and Andrade [28] reported a decrease in the lignin content of coconut fiber from 38.1% to 22.23-23.55% when using alkaline treatment.…”