The production of biodegradable polymers as alternatives to petroleum-based plastics has gained significant attention in the past years. To this end, polylactic acid (PLA) constitutes a promising ...alternative, finding various applications from food packaging to pharmaceuticals. Recent studies have shown that d-lactic acid plays a vital role in the production of heat-resistant PLA. At the same time, the utilization of renewable resources is imperative in order to decrease the production cost. This review aims to provide a synopsis of the current state of the art regarding d-lactic acid production
fermentation, focusing on the exploitation of waste and byproduct streams. An overview of potential downstream separation schemes is also given. Additionally, three case studies are presented and discussed, reporting the obtained results utilizing acid whey, coffee mucilage and hydrolysate from rice husks as alternative feedstocks for d-lactic acid production.
Numerous compounds obtained from the medicinal mushroom Ganoderma lucidum have evidenced renowned bioactive characteristics. Controlled fermentation to generate fungal mycelia confers several ...advantages, specifically when the valorization of agro-industrial streams as fermentation feedstocks is included. Submerged fermentation of a newly isolated Greek strain of G. lucidum was performed using conventional synthetic media and, also, grape pomace extract (GPE) and cheese whey permeate (CWP) under static and shaking conditions. Under shaking conditions, maximum biomass with GPE and supplementation with organic nitrogen reached 17.8 g/L. The addition of an elicitor in CWP resulted in a significant improvement in biomass production that exceeded synthetic media. Overall, agitation demonstrated a positive impact on biomass productivity and, therefore, on process optimization. Crude intracellular and extracellular polysaccharides were extracted and evaluated regarding antioxidant activity and polysaccharide and protein content. FTIR analysis confirmed the preliminary chemical characterization of the crude extracts. This study introduces the design of a bioprocessing scenario to utilize food industry by-products as onset feedstocks for fungal bioconversions to obtain potential bioactive molecules within the concept of bioeconomy.
The addition of natural components with functional properties in novel food formulations confers one of the main challenges that the modern food industry is called to face. New EU directives and the ...global turn to circular economy models are also pressing the agro-industrial sector to adopt cradle-to-cradle approaches for their by-products and waste streams. This review aims to present the concept of “sustainable functional compounds”, emphasizing on some main bioactive compounds that could be recovered or biotechnologically produced from renewable resources. Herein, and in view of their efficient and “greener” production and extraction, emerging technologies, together with their possible advantages or drawbacks, are presented and discussed. Μodern examples of novel, clean label food products that are composed of sustainable functional compounds are summarized. Finally, some action plans towards the establishment of sustainable food systems are suggested.
Lactic acid (LA) was produced on a pilot scale using a defined medium with glucose, acid whey, sugar bread and crust bread. The fermentation broths were then subjected to micro- and nanofiltration. ...Microfiltration efficiently separated the microbial cells. The highest average permeate flow flux was achieved for the defined medium (263.3 L/m²/h) and the lowest for the crust bread-based medium (103.8 L/m²/h). No LA losses were observed during microfiltration of the acid whey, whilst the highest retention of LA was 21.5% for crust bread. Nanofiltration led to high rejections of residual sugars, proteins and ions (sulphate, magnesium, calcium), with a low retention of LA. Unconverted sugar rejections were 100% and 63% for crust bread and sugar bread media respectively, with corresponding LA losses of 22.4% and 2.5%. The membrane retained more than 50% of the ions and proteins present in all media and more than 60% of phosphorus. The average flux was highly affected by the nature of the medium as well as by the final concentration of LA and sugars. The results of this study indicate that micro- and nanofiltration could be industrially employed as primary separation steps for the biotechnologically produced LA.
Lactic acid is an important chemical as starting chiral material in various applications. It has increased value in the global market. Different studies have presented the possibility to obtain rich ...lactic acid solutions with high isomeric purity (S-form) from second-generation (2G) feedstocks. The used downstream process is crucial, not only in terms of the overall cost but also for the achievement of high product purity, suitable for high-value applications. This review provides an overview of the current state-of-the-art on the separation and purification methods of lactic acid derived from the fermentation of second-generation feedstocks. The traditional precipitation method, solvent extraction, affinity-related processes, membrane separation, reaction-separation systems, salting-out extraction and molecular distillation are the main processes investigated so far. The different approaches are discussed in terms of lactic acid recovery yield and purity as well as their environmental impact.
Succinic acid production from the monosaccharides xylose, arabinose, glucose, mannose and galactose was studied using the bacterium
Actinobacillus succinogenes.
In Duran bottle cultures, containing ...10 g/L of each of sugar, succinic acid was produced from all sugars except for galactose. The highest succinate yield, 0.56 g/g, was obtained with glucose, whereas the succinate yield was 0.42, 0.38 and 0.44 g/g for xylose, mannose and arabinose, respectively. The specific succinate productivity was 0.7 g/g h for glucose, but below 0.2 g/g h for the other sugars. Batch bioreactor fermentations were carried out using a sugar mixture of the five sugars giving a total concentration of 50 g/L, mimicking the distribution of sugars in spent sulfite liquor (SSL) from Eucalyptus which is rich in xylose. In this mixture, an almost complete conversion of all sugars (except galactose) was achieved resulting in a final succinate concentration of 21.8–26.8 g/L and a total yield of 0.59–0.68 g/g. There was evidence of co-consumption of glucose and xylose, whereas mannose was consumed after glucose. The main by-products were acetate 0.14–0.20 g/g and formate 0.08–0.13 g/g. NADH balance calculations suggested that NADH required for succinate production was not met solely from formate and acetate production, but other means of NADH production was necessary. Results from mixed sugar fermentations were verified using SSL as substrate resulting in a succinate yield of 0.60 g/g. In addition, it was found that CO
2
sparging could replace carbonate supply in the form of MgCO
3
without affecting the succinate yield.
The side streams derived from the palm oil production process, namely palm kernel cake, palm pressed fibre, palm kernel shells and empty fruit bunches, were evaluated as sources of phenolic ...compounds. Among these streams, kernel cake had the highest total phenolic content (in mg of gallic acid equivalents (GAE) per g of dry sample) with a value of 5.19, whereas the empty fruit bunches had the lowest value (1.79). The extraction time and liquid-to-solid ratio were investigated to optimize the phenolic extraction. Kernel cake exhibited the highest total phenolic content (5.35 mg/g) with a liquid-to-solid ratio of 40:1 during 20 min of extraction. The main phenolic compounds of the extracts deriving from all byproduct streams were also identified and quantified with HPLC-DAD. Pyrogallol, 4-hydroxybenzoic acid, gallic acid and ferulic acid were the main compounds found in kernel cake extracts. Empty fruit bunch and pressed fibre extracts were also rich in 4-hydroxybenzoic acid, while pyrogallol was the predominant compound in kernel shell extracts. All extracts showed antioxidant activity as it was indicated from the results of DPPH analysis and subsequently tested in sunflower oil aiming to prolong its shelf life. The addition of 0.8% kernel cake extract increased the induction time of sunflower oil more than 50%. According to the results obtained in this study, kernel cake extracts could be considered as a value-added co-product with a potential application as antioxidants in the food industry.
Biotechnologically produced carotenoids occupy an important place in the scientific research. Owing to their role as natural pigments and their high antioxidant properties, microbial carotenoids have ...been proposed as alternatives to their synthetic counterparts. To this end, many studies are focusing on their efficient and sustainable production from renewable substrates. Besides the development of an efficient upstream process, their separation and purification as well as their analysis from the microbial biomass confers another important aspect. Currently, the use of organic solvents constitutes the main extraction process; however, environmental concerns along with potential toxicity towards human health necessitate the employment of "greener" techniques. Hence, many research groups are focusing on applying emerging technologies such as ultrasounds, microwaves, ionic liquids or eutectic solvents for the separation of carotenoids from microbial cells. This review aims to summarize the progress on both the biotechnological production of carotenoids and the methods for their effective extraction. In the framework of circular economy and sustainability, the focus is given on green recovery methods targeting high-value applications such as novel functional foods and pharmaceuticals. Finally, methods for carotenoids identification and quantification are also discussed in order to create a roadmap for successful carotenoids analysis.
We report the case of a 64-year-old male who died suddenly short after his admission to hospital because of strong chest pain and before any clinical diagnosis was established. His medical history ...included coronary disease with coronary by-pass surgery at the age of 40 years old, uncontrolled hypertension, diabetes mellitus, and elevated levels of cholesterol. The autopsy revealed quite a rare case of Stanford A aortic dissection with extension to the common and internal carotid arteries; the subclavian, axillary, brachial, and radial arteries; three coronary arteries; the superior mesenteric artery; and the iliac arteries. There was no histological evidence of aortitis or connective tissue disease. The death did not result from the rupture of the aortic dissection, but from myocardial ischemia due to coronary occlusion in combination with hemodynamic disturbance from stress caused by the extended aortic dissection.
The development of innovative functional products with potential health benefits, under the concept of bio-economy, is flourishing. This study undertook an evaluation of non-dairy lactobacilli ...Lactiplantibacillus pentosus B329 and Lactiplantibacillus plantarum 820 as “ready to use” starter cultures. Lactic acid bacteria (LAB) cultures were evaluated for their fermentation efficiency, before and after freeze-drying, using cheese whey (CW) as a fermentation substrate and subsequent immobilization on bacteria cellulose (BC) to produce a novel biocatalyst. The biocatalyst was applied in functional sour milk production and compared with free cells via the assessment of physicochemical and microbiological properties and sensory evaluation. Evidently, LAB strains exhibited high fermentative activity before and after freeze-drying. Results of a 5-month storage stability test showed that viability was 19% enhanced by immobilization on BC, supporting the concept of “ready to use” cultures for the production of fermented beverages. Likewise, sour milk produced by the BC biocatalyst presented higher organoleptic scores, compared to the free cells case, whereas immobilization on BC enhanced probiotic viability during post-fermentation storage (4 °C, 28 days). The obtained high viability (>107 log cfu/g) demonstrated the efficacy of the proposed bioprocess for the production of functional/probiotic-rich beverages. Ultimately, this work presents a consolidated scheme that includes the advantages and the cooperative effect of probiotic LAB strains combined with a functional biopolymer (BC) towards the formulation of novel functional products that coincide with the pillars of food systems sustainability.