Scalable production of bio-calcium oxide via thermal decomposition of solid - hatchery waste in a laboratory-scale rotary kiln

Chicken eggshell waste is an alternative renewable source for quicklime production. Eggshell waste has received significant attention from researchers due to it being a potential source of bio-CaO, which not only drives the circular economy concept but also supports sustainable development. However, experiments on the production of bio-CaO are normally conducted in a small lab-scale furnace. Furthermore, the eggshell raw material is collected from canteens or households, which is not suitable for economical or industrial production. Therefore, this study investigated the factors affecting the bio-CaO production from hatchery waste via both batch and continuous calcination process in a laboratory-scale rotary kiln for the first time. The eggshells were first separated from the solid hatchery waste. Then, the effect of preparation methods of raw eggshells on the properties of bio-CaO was investigated, including eggshells with and without membrane separation, various particle sizes, and with an increase of the percent raw material filling in the kiln from 5 to 20%. Calcination of the samples was performed in a rotary kiln at 800 °C with a 0.5 RPM rotating speed and a 5° inclination of the kiln. The effects of the calcination process in either an air or N2 atmosphere on the calcined product were also observed. Instrumental analysis shows that the production yield and purity of bio-CaO were in the range of 49-56 wt% and 97-98%, respectively. The results also indicated that the production yield of bio-CaO decreased to 17.7% with a decrease in the raw material particle size from 3.3 mm to 250 μm. Moreover, the production of bio-CaO with eggshells containing eggshell membrane decreases the purity of calcium oxide by about 0.7-1.0%. In addition, further increasing the filling volume of the kiln from 5 to 20% had only a slight effect on the purity and yield of the product. These results imply that it is not necessary to remove the eggshell membrane from the raw eggshells in order to produce industrial-grade CaO from the raw eggshell. These new findings can likely be used to develop an alternative process design to reduce the manufacturing cost of bio-CaO produced from hatchery waste. Furthermore, this present study reveals that the specifications of the obtained bio-CaO comply with both Thai industrial standards and international food additive standards.

A Sustainable, Green-Processed, Ag-Nanoparticle-Incorporated Eggshell-Derived Biomaterial for Wound-Healing Applications

The eggshell membrane (ESM) is a natural biomaterial with unique physical and mechanical properties that make it a promising candidate for wound-healing applications. However, the ESM's inherent properties can be enhanced through incorporation of silver nanoparticles (AgNPs), which have been shown to have antimicrobial properties. In this study, commercially produced AgNPs and green-processed AgNPs were incorporated into ESM and evaluated for their physical, biological, and antimicrobial properties for potential dermal application. The ESM was extracted using various techniques, and then treated with either commercially produced AgNPs (Sigma-Aldrich, Poole, UK) or green-synthesized AgNPs (Metalchemy, London, UK) to produce AgNPs-ESM samples. The physical characteristics of the samples were evaluated using scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and the biological properties were assessed through in vitro studies using human dermal fibroblasts (HDFs) and BJ cells. The SEM analysis of the AgNPs-ESM samples showed localization of AgNPs on the ESM surface, and that the ESM maintained its structural integrity following AgNP incorporation. The FTIR confirmed loading of AgNPs to ESM samples. The biological studies showed that the 5 μg/mL AgNPs-ESM samples were highly biocompatible with both HDFs and BJ cells, and had good viability and proliferation rates. Additionally, the AgNPs-ESM samples demonstrated pro-angiogenic properties in the CAM assay, indicating their potential for promoting new blood vessel growth. Assessment of the antimicrobial activity of the enhanced AgNPs/ESMs was validated using the International Standard ISO 16869:2008 methodology and exploited Cladosporium, which is one of the most commonly identified fungi in wounds, as the test microorganism (≥5 × 106 cells/mL). The AgNPs-ESM samples displayed promising antimicrobial efficacy as evidenced by the measured zone of inhibition. Notably, the green-synthesized AgNPs demonstrated greater zones of inhibition (~17 times larger) compared to commercially available AgNPs (Sigma-Aldrich). Although both types of AgNP exhibited long-term stability, the Metalchemy-modified samples demonstrated a slightly stronger inhibitory effect. Overall, the AgNPs-ESM samples developed in this study exhibited desirable physical, biological, and antimicrobial properties for potential dermal wound-dressing applications. The use of green-processed AgNPs in the fabrication of the AgNPs-ESM samples highlights the potential for sustainable and environmentally friendly wound-healing therapies. Further research is required to assess the long-term biocompatibility and effectiveness of these biomaterials in vivo.

The investigation of batch-to-batch variabilities in the composition of isolates from fish and mammalian species using different protocols

The aim of this study was to investigate batch-to-batch inconsistencies in the processing of pig and fish collagen isolates processed using two protocols that differed in terms of the acetic acid concentrations applied and the pre- and post-extraction steps, and which were previously tested in our laboratory with the intention of preserving the biological structures and functions of the collagen isolates for biomedical purposes. Both the major and minor components such as the amino acids, lipids, water, glycosaminoglycan and ash contents and elemental content, as well as the structure and morphology of the raw sources and the resulting batches of isolates were subsequently examined in detail applying standardized analytical methods including high perfomance liquid chromatography, ultraviolet-visible and infrared spectrometry, polyacrylamide gel electrophoresis, energy dispersive spectroscopy and scanning electron microscopy. All the fish isolates provided severalfold higher yields (8-45 wt%) than did the pig isolates (3-9 wt%). In addition, the variability of the fish isolate yields (the coefficient of variation for processing A: 16.4-32.9 % and B: 6.8-17.4 %) was significantly lower (p ≤ 0.05, n = 5) than that of the pig isolates (A: 27.7-69.8 %; B: 35.3-87.9 %). In general, the fish skin batches had significantly higher protein contents (˃60 wt%) and lower lipid contents (<10 wt%) than the pig skin batches (<55 wt% protein and up to 66 wt% lipid). In addition, the fish skin batches did not differ significantly in terms of their composition applying the same processing method, whereas the pig skin batches exhibited considerable variations in terms of their compositions, particularly regarding the protein and lipid contents. It can be stated that, concerning the fish isolates, processing B was, in most cases, slightly more efficient and reproducible than processing A. However, concerning the pig isolates, although processing A appeared to be more efficient than processing B in terms of the yield, it resulted in the production of isolates that contained a certain level of contaminants. The study provides a comprehensive discussion on the suitability of the processing protocol in terms of producing batches of reproducible quality according to the specific type of biomaterial processed from different animal species.

High value applications and current commercial market for eggshell membranes and derived bioactives

Chicken eggshell membrane (ESM) is a highly insoluble structure that is greatly stabilized by extensive desmosine, isodesmosine, and disulfide cross-linkages. The ESM possesses numerous biological functions including anti-microbial, anti-inflammatory, anti-wrinkle, and antioxidant activities. The ESM is mainly proteinaceous; proteomics and bioinformatics analysis of ESM has identified > 500 proteins, such as collagens, glycoproteins, avian beta-defensins, and lysozyme. ESM also contains significant amounts of carbohydrate, including hyaluronic acid (HA). In general, HA plays an important role in tissue hydration and cellular mechanisms such as growth, differentiation, and transport, and has diverse health and medical applications. Despite ESM being rich in important bioactive compounds, it is often considered as a waste product of the egg-breaking industry and is under-utilized. A major challenge for the successful commercial exploitation of ESM and bioactive constituents is its limited solubility and bioavailability due to cross-linkages of ESM fibers. Various processing and extraction methods are employed to overcome these limitations and improve the production of HA and collagen-based ESM formats. Moreover, we believe that there is a wide scope to exploit ESM for novel applications, leading to new intellectual property (IP) and patenting opportunities. This review presents an overview of scientific background, IP landscape and current commercial market for ESM and derived bioactives including collagens and HA. A detailed literature survey is provided for each area of interest. We analyze regulatory guidelines for ESM, contrasting quality control / microbial safety assessment in cosmetics and personal care products (hazard based) with that of the food industry (risk-based). New perspectives for upcycling of ESM waste to commercially viable high-value biomaterials as nutraceutical supplements and as cosmetics ingredients are discussed. This overview of ESM separation techniques and applications could form the basis for directed research and product development in order to exploit the unique bioactivities of ESM.

Process optimization for extraction of avian eggshell membrane derived collagen for tissue engineering applications

The avian eggshell membranes’ composition depicts close resemblance with the extracellular matrix of the cells, and therefore being widely employed as potential biomaterials for tissue engineering applications. However, the optimization of process conditions for collagen extraction, the main constituent of eggshell membranes is still challenging. In the present study, extraction of collagen was performed by an enzymatic method optimized through the one-factor-at-a-time (OFAT) technique for three parameters viz. pepsin concentration, treatment time and pH. The process optimization resulted in the maximum yield of 56% collagen with 350 U/mg pepsin concentration at pH 3 treated for 9 days, not reported yet. The collagen extraction was confirmed by OD at 232 nm; and its viscoelasticity behaviour at pH 5. The physico–chemical characterization of extracted collagen with FESEM, ATR-FTIR, surface roughness analysis and contact angle measurement revealed the morphological and topological alteration during the collagen extraction. The process optimization and characterization of eggshell membrane derived collagen can aid in the significant biomaterials development for tissue regeneration.

A review on recent advances of egg byproducts: Preparation, functional properties, biological activities and food applications

The rapid development of egg industries produced vast byproducts that have not been effectively used. In this paper, the comprehensive utilization of egg byproducts was reviewed. Protein extraction and enzymatic hydrolysis were the main used ways for recycle of egg byproducts. The fact that eggshell membrane could accelerate would healing and improve facial skin of healthy people for 12 weeks was found. However, salted egg white had poor functional properties owing to high salt and ultrafiltration was an effective technology to remove 92.93% of salt. Moreover, Defatted yolk protein had the great potential to be used as food additives and functional foods. Other egg byproducts such as egg inhibitor and eggshells also were discussed. The novel applications of egg byproducts in the food field included food additives, feeds, food packaging materials and nutraceuticals based on current knowledge, but the proportion needed to be improved. This paper would provide a new insight for comprehensive utilization of egg byproducts.