Biorecovering of phenolic-rich compounds from food industry wastes

In food industry, abundant fruit/vegetable byproducts (peel, seed, etc.) have been generated and released into the environment. These wastes can be considered as a largely available, low-cost source of value-added compounds. Among these, phenolic compounds are well-known for their beneficial effects on human health. Effective extraction methodologies are required for recovery of these phenolic compounds from agri-food wastes. These extracts can be used used as natural antimicrobials in pharmacology or disinfectants in food processing plants. In this work, pomegranate peel extracts were prepared by using different solvents to obtain high amount of phenolic-rich compounds. The pomegranate peel extracts were also tested against some important food pathogens to determine their antimicrobial and antibiofilm activities. Pomegranate peel extracts having high amount of phenolic compounds had higher antimicrobial and antibiofilm activities. As a result, phenolic-rich bioactive compounds can be recovered from food industry wastes and used as natural antimicrobial and antibiofilm agents. Thus, food industry wastes, especially fruit wastes, can be integrated into the extraction process and use in food, pharmacology, cosmetic and medicine industries.

Antimicrobial Activities of Olive Oil Mill Wastewater Extracts against Selected Microorganisms

Discovering eco-friendly alternatives to synthetic chemicals has become an increasingly popular area of research. Natural products are now in the spotlight for their potential use as replacements for synthetic chemicals. To maximize the benefits of these natural products, it is important to use efficient extraction methods, especially from agroindustrial waste. Olive oil mill wastewater (OOMW) is a byproduct of the olive oil production process and is considered a pollutant; however, OOMW contains a wide range of phenolic compounds that have proven antimicrobial properties. This study investigates the extraction of these compounds from OOMW, with the aim of determining their potential antimicrobial activities against several bacterial strains and fungi, including Bacillus spizizenii, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella aerogenes, Streptococcus uberis, Enterococcus faecalis, and Candida albicans. The OOMW extracts (OEs) were prepared by using three different solvents: ethyl acetate, ethanol, and methanol. The highest total phenolic contents (4.03 g, GAE/L) and the strongest antibacterial activity were obtained with methanol extraction. All OEs showed no antifungal activity against C. albicans. OEs, particularly methanol extracts of OOMW, can be used as bioactive substances in various industries as nutraceuticals and food ingredients, respectively

Investigation of growth properties of Paenibacillus strains in the presence of 2-HBP

Crude oil and fossil fuels contain sulphur compounds. Consumption of these compounds could cause acid rain and environmental pollution. Dibenzothiophene (DBT) is considered as model compound for investigation of fossil fuel desulphurization. This compound is converted to 2-HBP following bio-desulphurization (BDS) by 4S pathway. This work aimed to investigate bacterial growth properties in the presence of 2-HBP which is a final product of DBT desulphurization. For this, two Paenibacillus strains (32 O-W and 32 O-Y) were incubated in 2-HBP (to give the final concentrations at 0.05, 0.1, and 0.2 mM) containing growth media. Although the OD600 value of the 32 O-W strain was low at all 2-HBP concentrations, the 32 O-Y strain could survive, and its OD levels were 3–4 fold higher than 32 O-W strain. As a result, it can be interpreted that the final products of DBT metabolism did not too toxic, and thus bio-desulfurization can be successfully completed by Paenibacillus strains. Acknowledgments: This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK, 118Y416)

Effective ethanol production from whey powder through immobilizedE. coliexpressingVitreoscillahemoglobin

Ethanol production from whey powder was investigated by using free as well as alginate immobilized E. coli and E. coli expressing Vitreoscilla hemoglobin (VHb) in both shake flask and fermenter cultures. Media with varying levels of whey (lactose contents of 3%, 5%, 8% or 15%) and yeast extract (0.3% or 0.5%) were evaluated with fermentation times of 48–96 h. Immobilization and VHb expression resulted in higher ethanol production with all media; the increases ranged from 2% to 89% for immobilization and from 2% to 182% for VHb expression. It was determined that growth medium containing 8% lactose with 0.5% yeast extract yielded the highest ethanol production for free or immobilized strains, with or without VHb expression, in both shake flask and fermenter cultures. Immobilization with alginate was found to be a promising process for ethanol production by VHb-expressing ethanologenic E. coli.

Antibiofilm effects of pomegranate peel extracts against B. cereus, B. subtilis and E. faecalis

In this study, the antibacterial and antibiofilm properties of pomegranate (Punica granatum L.) extracts (PPLs) prepared by 10g of pomegranate peels (PPL10) and 100 mL of different solvents (ethanol, methanol, and their acid combinations, and water) were investigated as sources of bioactive compounds against food related bacteria. The antimicrobial activities of the extracts were measured by using agar well diffusion assay. The acid-treated extracts exhibited the highest antimicrobial activities (31-34 mm). The biofilm formations were assessed by using a microplate reader (570 nm) after crystal violet staining. The prevention and removal of bacterial biofilms were also evaluated by using extracts prepared by 5g of initial pomegranate peel (PPL5) with the different solvents or 200 ppm chlorine solution. All PPL5 and PPL10 extracts diluted at different ratios inhibited and removed biofilms and the highest antibiofilm effects were up to 80% by acid-treated extracts. In addition, PPL5s and PPL10s were as effective as or more effective than chlorine for the prevention of biofilms. Therefore, from an economical perspective the PPL5s could represent promising candidates as natural antibiofilm agents for food industry. 

Novel Perspectives on Food-Based Natural Antimicrobials: A Review of Recent Findings Published since 2020

Various fruit and vegetable wastes, particularly peels, seeds, pulp, and unprocessed residues from the food industry, are abundant sources of antioxidants and essential antimicrobial agents. These valuable bioactive compounds recovered from the food industry have a great application in food, agriculture, medicine, and pharmacology. Food-derived natural antimicrobials offer advantages such as diminishing microbial loads and prolonging the shelf life of food products particularly prone to microbial spoilage. They not only enrich the foods with antioxidants but also help prevent microbial contamination, thereby prolonging their shelf life. Similarly, incorporating these natural antimicrobials into food packaging products extends the shelf life of meat products. Moreover, in agricultural practices, these natural antimicrobials act as eco-friendly pesticides, eliminating phytopathogenic microbes responsible for causing plant diseases. In medicine and pharmacology, they are being explored as potential therapeutic agents. This review article is based on current studies conducted in the last four years, evaluating the effectiveness of food-based natural antimicrobials in food, agriculture, medicine, and pharmacology

Repeated batch fermentation of immobilized E. coli expressing Vitreoscilla hemoglobin for long-term use

This study describes an efficient and reusable process for ethanol production from medium containing whey powder, using alginate immobilized ethanologenic E. coli strains either expressing (TS3) or not expressing (FBR5) Vitreoscilla hemoglobin. Reuseabilities of the FBR5 and TS3 strains were investigated regarding their ethanol production capacities over the course of 15 successive 96-h batch fermentations. The ethanol production was fairly stable over the entire duration of the experiment, with strain TS3 maintaining a substantial advantage over strain FBR5. Storage of both strains in 2 different solutions for up to 60 d resulted in only a modest loss of ethanol production, with strain TS3 consistently outperforming strain FBR5 by a substantial amount. Strains stored for 15 or 30 d maintained their abilities to produce ethanol without dimunition over the course of 8 successive batch fermentations; again strain TS3 maintained a substantial advantage over strain FBR5 throughout the entire experiment. Thus, immobilization is a useful strategy to maintain the advantage in ethanol productivity afforded by expression of Vitreoscilla hemoglobin over long periods of time and large numbers of repeated batch fermentations, including, as in this case, using media with food processing wastes as the carbon source.

Effects of fungal based bioactive compounds on human health: Review paper

Since the first years of history, microbial fermentation products such as bread, wine, yogurt and vinegar have always been noteworthy regarding their nutritional and health effects. Similarly, mushrooms have been a valuable food product in point of both nutrition and medicine due to their rich chemical components. Alternatively, filamentous fungi, which can be easier to produce, play an active role in the synthesis of some bioactive compounds, which are also important for health, as well as being rich in protein content. Therefore, this review presents some important bioactive compounds (bioactive peptides, chitin/chitosan, β-glucan, gamma-aminobutyric acid, L-carnitine, ergosterol and fructooligosaccharides) synthesized by fungal strains and their health benefits. In addition, potential probiotic- and prebiotic fungi were researched to determine their effects on gut microbiota. The current uses of fungal based bioactive compounds for cancer treatment were also discussed. The use of fungal strains in the food industry, especially to develop innovative food production, has been seen as promising microorganisms in obtaining healthy and nutritious food

Pyrolyzed bacterial cellulose-supported SnO2 nanocomposites as high-capacity anode materials for sodium-ion batteries

International audienceRoom-temperature sodium-based batteries have the potential for meeting large-scale grid energy storage needs. Inspired by the advancement of the design and building of electrode materials in lithium ion batteries, improved nano-architectured electrodes can be created for sodium-ion batteries, allowing increased electron transport kinetics and conductivities. Here, nanocomposites with 3D porous structures are reported as a high-capacity anode material for sodium-ion batteries by using an easy, low-cost and environmentally friendly synthesis of pyrolyzed bacterial celluloses (PBCs). Bacterial celluloses (BCs) produced by the Gluconacetobacter xylinus strain are pyrolyzed at 500, 750 and 1000 A degrees C, resulting 50, 130 and 110 mAh g(-1) capacities over 80 numbers of cycles, respectively, in the presence of the binary ethylene carbonate-propylene carbonate mixture. In order to increase the cell performances, in situ coated SnO2 nanoparticles with bacterial cellulose (SnO2@PBC) are produced by addition as synthesized 5-nm-sized SnO2 nanoparticles into the BC growth medium together with the G. xylinus strain. Following the pyrolysis at 500 A degrees C, the SnO2@PBC composite is better able to handle the accommodation of the dramatic volume change of the incorporated SnO2 nanoparticles because of the interaction of oxygen-containing moieties of bacterial cellulose nanofibrils with the SnO2 nanoparticles during cellulose production. The resulting SnO2@PBC composite presents highly stable capacity retention of around 400 mAh g(-1) capacities at C/10 current density over 50 numbers of cycles