Formulation of a fermentation substrate from pineapple and sacha inchi wastes to grow Weissella cibaria

Biosurfactant Production from Pineapple Waste and Application of Experimental Design and Statistical Analysis

The use of non-conventional carbon sources for biosurfactant-producing microorganisms is a promising alternative in fermentation to substitute costly substrates. So, the current research used pineapple peel as a cost-effective and renewable substrate because of its rich composition in minerals and sugars and high availability. Following a 2² full factorial design, a bacterial strain of Bacillus subtilis produced biosurfactants in fermentative media containing different concentrations of glucose and concentrated pineapple peel juice (CPPJ). The influence of these two independent variables was evaluated according to three different responses: surface tension reduction rate (STRR), emulsification index (EI₂₄), and concentration of semi-purified biosurfactant (SPB). The maximum value for STRR (57.63%) was obtained in media containing 0.58% glucose (w/v) and 5.82% CPPJ (v/v), while the highest EI₂₄ response (58.60%) was observed at 2% glucose (w/v) and 20% CPPJ (v/v) and maximum SPB (1.28 g/L) at 3.42% glucose (w/v) and 34.18% CPPJ (v/v). Statistical analysis indicated that the CPPJ variable mostly influenced the STRR and SPB responses, whereas the EI₂₄ was significantly influenced by pineapple peel juice and glucose contents.

Assessment of Different Lactic Acid Bacteria Isolated from Agro-Industrial Residues: First Report of the Potential Role of Weissella soli for Lactic Acid Production from Milk Whey

The production of lactic acid (LA) through the microbial conversion of agro-industrial residuals is an important process in the biotechnology industry. The growth kinetics of 30 strains of lactic acid bacteria (LAB) isolated from agro-industrial residues were determined and nine strains were selected for microbioreactor fermentation. Lactiplantibacillus pentosus_70-1 (1.662) and L. pentosus_19-2 (1.563) showed the highest OD600 values, whereas the highest growth rates were observed for L. pentosus_19-2 (0.267 h−1) and Weissella soli_31 (0.256 h−1). The production of LA and acetic acid (AA), glucose consumption, and metabolic profiles were determined, without finding significant differences in the production of LA; however, W. soli_29 produced the highest amount of LA (20.833 gL−1) and was able to metabolize most of the studied carbohydrates. Based on these results, W. soli_29 was chosen for a 20 h fermentation in a 7 L bioreactor using both standard medium and milk whey supplemented medium. W. soli_29 produced 16.27 gL−1 and 7.21 gL−1 of LA in each of these mediums, respectively. These results show the underlying potential of Weissella strains for biotechnological applications. Additional analysis which should contemplate different agro-industrial residues and other conditions in bioreactors must be carried out.

Influence of Ultrasound Application in Fermented Pineapple Peel on Total Phenolic Content and Antioxidant Activity

Antioxidant phenolic compounds were extracted from fermented samples of Golden pineapple peels via an ultrasound method. The fermentation conditions to maximize the production of phenolic content and antioxidant activity were previously determined (pH: 5.5, T: 37.3 °C and 85% moisture content). A central composite design with 20 treatments was applied to evaluate the effect of the ethanol concentration, time, and temperature on the production of phenolic compounds and antioxidant activity of the extracts. The statistical analysis showed that the optimal conditions to produce extracts with high phenolic content and antioxidant activity were: 62 °C, 30 min and 58% ethanol. We obtained 866.26 mg gallic acid equivalents (GAE)/g d.m in total phenolic content and for antioxidant activity expressed as percentage inhibition, 80.06 ± 1.02% for ABTS and 63.53 ± 2.02% for DPPH, respectively. The bioactive compound profile in the extracts was identified and quantified using ultra-high performance liquid chromatography (UHPLC), this method showed the presence of rosmarinic acid, caffeic acid, vanillic acid, p-coumaric acid, ferulic acid, quercetin-3 glucoside, rutine, quercetin, kaempherol-3 glucoside and gallic acid, demonstrating the great potential of these by-products to obtain components that can benefit the consumer’s health.

Procyanidins: From Agro-Industrial Waste to Food as Bioactive Molecules

Procyanidins are an important group of bioactive molecules known for their benefits to human health. These compounds are promising in the treatment of chronic metabolic diseases such as cancer, diabetes, and cardiovascular disease, as they prevent cell damage related to oxidative stress. It is necessary to study effective extraction methods for the recovery of these components. In this review, advances in the recovery of procyanidins from agro-industrial wastes are presented, which are obtained through ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, pressurized fluid extraction and subcritical water extraction. Current trends focus on the extraction of procyanidins from seeds, peels, pomaces, leaves and bark in agro-industrial wastes, which are extracted by ultrasound. Some techniques have been coupled with environmentally friendly techniques. There are few studies focused on the extraction and evaluation of biological activities of procyanidins. The identification and quantification of these compounds are the result of the study of the polyphenolic profile of plant sources. Antioxidant, antibiotic, and anti-inflammatory activity are presented as the biological properties of greatest interest. Agro-industrial wastes can be an economical and easily accessible source for the extraction of procyanidins.

Bioconversion of Apple Pomace into Microbial Protein Feed Based on Extrusion Pretreatment

Apple pomace (AP) is often used directly as animal feed, while the value of feeding is limited by its low protein content. In this study, extrusion pretreatment was performed for AP, and further fermentation was carried out to improve its nutrition value. Strains suitable for extruded apple pomace (EAP) to produce high-quality microbial protein (MP) feed were screened from 12 different strains. Results showed that Aspergillus niger 3.324 (Asn), Candida utilis1314 (Cau), Geotrichum candidum 1315 (Gec), Bacillus subtilis A308 (Bas1), and Lactic acid bacteria (Lac) were screened as the dominant strains, which exhibited higher feeding value. Strong symbiotic effect was observed in fermentation with mixed strains of Asn, Cau, Gec, and Lac at the ratio of 1:1:1:1. Compared with AP, the pure protein content in the optimized fermented EAP (FEAP) was increased by 138% accompanying with a pleasant flavor and taste. And its pure protein content was increased by 19.20% in comparison to that of the fermented apple pomace. The nutrition value of FEAP was characterized by amino acid profiles; it found that FEAP was comparable to other commercial proteins with higher contents of histidine, phenylalanine, threonine, and valine. Combination of fermentation and extrusion technology significantly enhanced pure protein content and nutritional composition of apple pomace, which was revalorized as a nutritive animal feed rich in microbial protein.

Optimization of the reproduction of Weissella cibaria in a fermentation substrate formulated with agroindustrial waste

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Use of pineapple and sacha inchi wastes in biotechnological processes.

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Valorization of agroindustrial waste in the context of circular economy.

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Use of alternative fermentation substrates (SFS) in the production of probiotics (Weissella cibaria), in order to substitute conventional substrates.

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Optimal conditions of the fermentation process for the reproduction and viability of W. cibaria.

Agroindustrial wastes contain macronutrients and micronutrients essential for the reproduction of lactic acid bacteria. In this research, the reproduction of Weissella cibaria was experimentally optimized in a supplemented fermentation substrate (SFS) formulated from pineapple and sacha inchi wastes. Response surface methodology was used to evaluate the influence of the following independent variables: temperature (32–40 °C), pH (5.0–6.0), and stirring speed (SS) (100–150 rpm) on the following dependent variables: viability (Log₁₀ CFU mL⁻¹), biomass production (B_Wc), lactic acid production (LA), biomass yield (Y_Bwc/S), biomass volumetric productivity (VP_Wc), LA volumetric productivity (VP_LA), carbon source consumption (CSC), N₂ consumption (N₂C), and specific growth rate (µ). The experimental optimization of multiple responses presented a desirability of 76.8%, thus defining the independent variables of the process: temperature = 35.1 °C, pH = 5.0, and SS = 139.3 rpm; and the dependent variables: viability = 10.01 Log₁₀ CFU mL⁻¹, B_Wc = 2.9 g L⁻¹, LA = 19.4 g mL⁻¹, Y_Bwc/S = 43.9 g biomass/g CSC, VP_Wc = 0.49 g L⁻¹h ^− 1, VP_LA = 3.2 g L⁻¹ h⁻¹, CSC = 17.2%, N₂C = 63.6% and µ = 0.28 h⁻¹. From these, viability, Y_Bwc/S, CSC, N₂C, and LA presented significant statistical differences, while the independent variable with the least important effect on the process was pH. Under optimal conditions of temperature, pH and SS; SFS favors the reproduction and viability of W. cibaria. This provides evidence of a sustainable alternative for the production of probiotics in the context of circular economy.