Zero-waste Approach Research Articles

Assessment of Zero Waste Approach by Enhancing Chromium-to-Iron Ratio in Chromite Ore Through Magnetizing Roasting: A Novel Comparative Sustainable Study of Conventional and Hybrid Microwave Heating Methods

Assessment of Zero Waste Approach by Enhancing Chromium-to-Iron Ratio in Chromite Ore Through Magnetizing Roasting: A Novel Comparative Sustainable Study of Conventional and Hybrid Microwave Heating Methods

Valorization of agricultural by-product for cleaner and sustainable production of microbial pigments and cellulolytic enzymes in a zero-waste approach

This work presents a zero-waste concept for the valorization of banana peel into Monascus value-added metabolites, such as pigments and cellulolytic enzymes, and for evaluation of the feasibility of treated peel as a promising source for animal feedstuff. M. purpureus YRU01 exhibited satisfactory pigment and cellulolytic enzyme production in solid-state fermentation. Particularly, repeated solid-state fermentation of non-sterile peel with 90% substrate replacement was effective in offering high recovery of pigments, xylanase, and cellulase (7.19-, 31.19-, and 92.62-fold higher than those of solid-state fermentation, respectively). The LC/MS profile of fermented peel provided important evidence of fungal metabolites (>100 metabolites) for understanding and evaluating the fermentation. Moreover, citrinin-related mycotoxin fragments were not found. The treated peel had high carbohydrate, neutral detergent fiber, and acid detergent fiber contents, but low protein content, indicating its potential to be used as a roughage in animal feed.

Valorization of Pig Brains for Prime Quality Oil: A Comparative Evaluation of Organic-Solvent-Based and Solvent-Free Extractions.

Pig processing industries have produced large quantities of by-products, which have either been discarded or used to make low-value products. This study aimed to provide recommendations for manufacturing edible oil from pig brains, thereby increasing the value of pork by-products. The experiment compared non-solvent extraction methods, specifically wet rendering and aqueous saline, to a standard solvent extraction method, the Bligh and Dyer method, for extracting oil from pig brains. The yield, color, fatty acid profile, a number of lipid classes, and lipid stability against lipolysis and oxidation of the pig brain oil were comprehensively compared, and the results revealed that these parameters varied depending on the extraction method. The wet rendering process provided the highest extracted oil yield (~13%), followed by the Bligh and Dyer method (~7%) and the aqueous saline method (~2.5%). The Bligh and Dyer method and wet rendering techniques produced a translucent yellow oil; however, an opaque light-brown-red oil was found in the aqueous saline method. The Bligh and Dyer method yielded the oil with the highest phospholipid, cholesterol, carotenoid, tocopherol, and free fatty acid contents (p < 0.05). Although the Bligh and Dyer method recovered the most unsaturated fatty acids, it also recovered more trans-fatty acids. Aqueous saline and wet rendering procedures yielded oil with low FFA levels (<1 g/100 g). The PV of the oil extracted using all methods was <1 meq/kg; however, the Bligh and Dyer method had a significant TBARS content (7.85 mg MDA equivalent/kg) compared to aqueous saline (1.75 mg MDA equivalent/kg) and wet rendering (1.14 mg MDA equivalent/kg) (p < 0.05). FTIR spectra of the pig brain oil revealed the presence of multiple components in varying quantities, as determined by chemical analysis experiments. Given the higher yield and lipid stability and the lower cholesterol and trans-fatty acid content, wet rendering can be regarded as a simple and environmentally friendly method for safely extracting quality edible oil from pig brains, which may play an important role in obtaining financial benefits, nutrition, the zero-waste approach, and increasing the utilization of by-products in the meat industry.

Cold plasma/alkaline pretreatment facilitates corn stalk fractionation and valorization towards zero-waste approach

The present study employed alkaline hydrogen peroxide pretreatment coupled with cold plasma for corn stalk’s complex biopolymers fractionation and valorization through enzymatic hydrolysis. This hurdle approach enables the prolonged generation of reactive oxidative species, initiating chemical reactions otherwise hardly possible under ambient conditions. A delignification rate between 76±1 and 86±2 % was obtained under different process parameters in a significantly shorter time compared to conventional alkaline pretreatment. Up to 94±4 % of cellulose in treated biomass was converted to glucose after enzymatic hydrolysis, achieving around 3.5 times higher glucose yield than the raw biomass. Different spectroscopic analyses confirmed specific alterations in the structure of the lignin-rich fraction caused by cold plasma. Micro- and nanoscale lignin particles obtained were rich in total phenolic content, reaching up to 140±20 and 107±12 µg gallic acid equivalents (GAE) per mg of lignin, respectively. The proposed concept of corn stalk fractionation through biorefinery can open new opportunities for valorizing different agricultural waste types.

Exploring the Multifaceted Potential of Endangered Sturgeon: Caviar, Meat and By-Product Benefits.

Sturgeons are facing critical endangerment due to overfishing, habitat destruction, pollution and climate change. Their roe, highly prized as caviar, has driven the overexploitation, severely depleting wild populations. In recent years sturgeon aquaculture has experienced significant growth, primarily aimed at providing high-quality caviar and secondarily meat. This sector generates significant quantities of by-products, which are mainly treated as waste, being mostly discarded, impacting the environment, even though they are a source of bioactive molecules and potential applications in various sectors. This article presents a review of the proximate composition and nutritional value of sturgeon caviar and meat, also exploring the potential of the by-products, with an emphasis on the processing of these components, the chemical composition and the functional and bioactive properties. Although sturgeon caviar, meat, and by-products are highly valuable both nutritionally and economically, adopting sustainable practices and innovative approaches is crucial to ensuring the industry's future growth and maintaining ecological balance. Despite some limitations, like the deficient standardization of the methods for extracting and processing, sturgeon by-products have a tremendous potential to increase the overall value of sturgeon aquaculture and to promote a zero-waste approach, contributing to achieving the Sustainable Development Goals adopted by all United Nations Member States in 2015.

Biosorption of Remazol Brilliant Blue R textile dye using Clostridium beijerinckii by biorefinery approach.

The current study proposes RBBR biosorption by Clostridium beijerinckii DSMZ 6422 biomass remaining after biobutanol production from pumpkin peel (PP) by a zero-waste approach. Efficient biobutanol production was achieved by investigating initial PP concentrations (5-20% without or with enzymatic hydrolysis) and fermentation time. According to this, the highest concentrations of biobutanol and total ABE were obtained as 4.87g/L and 8.13g/L in the presence of 10% PP without enzymatic hydrolysis at 96h. Furthermore, based on the zero-waste approach, C. beijerinckii DSMZ 6422 biomass obtained after biofuel production was used as a biosorbent for the removal of RBBR dye. Response surface methodology (RSM), commonly utilized for the experimental design, was used to specify the optimized biosorption conditions of RBBR, including initial dye concentration (50-200mg/L), initial pH (2-6), biosorbent concentration (1-3g/L), and contact time (0-240min). The highest biosorption under optimized conditions with RSM was 98% in the presence of 194.36mg/L RBBR and 2.65g/L biosorbent at pH 2 and 15min. This is the first report in the literature about the biosorption of RBBR dye by anaerobic C. beijerinckii biomass after the biobutanol production process. This study also shows the efficient usage of agricultural and microbial wastes in different areas based on zero-waste applications.

The effect of biochar obtained from waste filter coffee grounds on plant germination

Nowadays, coffee consumption is quite high, and the consumption of filter coffee is steadily increasing. Consequently, there is a significant increase in waste filter coffee. This study aims to evaluate waste filter coffee grounds using a zero-waste approach. In this context, the solid product of pyrolyzed waste filter coffee grounds was added to the soil in specific ratios to improve soil quality and increase yield. The effects on the root and stem development of arugula (Eruca vesicaria) and garden cress (Lepidium sativum) plants were investigated. Waste filter coffee grounds was homogeneously mixed with soil at application rates of 1, 2, and 4 tons/ha. The results of the study observed that the pyrolysis solid product positively affected plant growth. Comparing the data, the highest yield in plants was observed in soil with added biochar, while lower yields were seen in soil with added raw waste filter coffee grounds, and the lowest yield was found in soil without biochar. Among the soils with added biochar, the most significant root and stem development was observed in plants with 2 tons/ha of added biochar.

A sustainable, zero-waste approach for production of biohydrogen from chicken manure slurry by hybrid recycling of digestate

This study provides a sustainable approach to produce biohydrogen through the long-term hydrogenic fermentation of chicken manure (CM) in a semi-continuous stirred tank reactor (CSTR) under different organic loading rates (OLRs). To ensure the zero-waste route and sustainability, the total digestate was mechanically separated into liquid and solid fractions. The solid digestate fraction was thermally treated to produce biochar, while the liquid digestate fraction was biologically treated through bioaugmentation with a novel heterotrophic nitrification-aerobic denitrification (HD-AN (bacterial strain (Alcaligenes sp. ME-1). The results showed that the high concentration of free ammonia nitrogen (FAN) contents of CM could inhibit methanogenesis and induce hydrogen production. The ORLs of 2.5, 3.5, 4.5, and 5.5 gVS/L.d imposed to the CSTR resulted in volumetric hydrogen production (VHP) of 643.3 ± 37, 908.8 ± 64.5, 1077.8 ± 95.17, and 1383.3 ± 156.8 mL/L.d, respectively. The microbial community structures indicated the long-term adaptation of hydrogen-producing bacteria and methanogenesis inhibition. The bioaugmentation process removed 83.3 % of total ammonia and 66.2 % of the chemical oxygen demand (COD) from the liquid digestate fraction. The characteristics of the biochar derived solid digestate is suitable for land applications as fertilizer. The hybrid approach combining biohydrogenation, pyrolysis, and bioaugmentation, maximizes the utilization of chicken manure slurry while conforming to the sustainable development goals.

Pioneering solutions for sustainable protein production in future

Pioneering solutions for sustainable protein production in future InnoProtein consortium, explain why sustainable protein production is urgently needed and how, with its circular, zero-waste approach, InnoProtein supports this goal. By 2050, population growth will play a major role in the state of the environmental, social and economic system. (1) Traditional protein products, with their vast amounts of animal derivates, are being presented as sustainably obsolete due to the high consumption of natural resources employed for their production. (2) Current protein production has a high environmental impact, and a general transition towards greener and sustainable consumption is required. Agriculture is responsible for 70-85% of the world’s water footprint and 30% of global GHG emissions. Meat production is the most impactful activity in food production.

Innovative Fermented Beverages Based on Bread Waste—Fermentation Parameters and Antibacterial Properties

Faced with challenges related to environmental degradation and the growing need for sustainable development, the food sector must look for innovative and ecological production solutions. One of the increasingly popular directions is the zero-waste approach, which limits waste generation and enables its reuse. This research aimed to evaluate selected quality indicators of the lactic acid fermentation process of beverages based on waste from the bakery industry (wheat–rye bread) to determine the optimal fermentation conditions using two strains of lactic acid bacteria: Lacticasibacillus paracasei and Lactiplantibacillus plantarum. Preliminary process optimization was carried out, taking into account the beverage composition, fermentation time, and starting culture. The process evaluation and the selection of the optimal variant were based on the microbiological quality, pH value, and antimicrobial activity of fermented beverages. The results showed that the bread waste may constitute a base for obtaining fermented beverages as evidenced by the high number of lactic acid bacteria, above 108 CFU/mL, and low pH values (≤3.5) after the appropriate incubation time. Fermented beverages exhibited antibacterial properties against tested indicator microorganisms, which confirmed their functional properties. The analysis of the obtained results and the adopted assumptions enabled the selection of the most optimal variant—the beverage with ground flaxseed, fermented by L. paracasei for 24 h. The conducted research indicates great potential for lactic acid fermentation in the management of bakery waste to create innovative, sustainable food products with probiotic potential.

Novel cold and thermally pasteurized cardoon-enriched functional smoothie formulations: A zero-waste manufacturing approach

This study investigated the potential of incorporating cardoon (Cynara cardunculus L.) blades as bioactive and dietary fiber ingredients in vegetable/fruit-based smoothies, within a zero-waste approach. The smoothie formulations were pasteurized by high-pressure (550 MPa for 3 min, HPP) and thermal (90 °C for 30 s, TP) treatments and stored at 4 °C for 50 days. Cardoon-fortified smoothies exhibited higher viscosity, darker color, increased phenolic compound levels, and greater anti-inflammatory and antioxidant activities. Furthermore, the cardoon blade ingredients contributed to a more stable dietary fiber content throughout the smoothies' shelf-life. HPP-processed smoothies did not contain sucrose, suggesting enzymatic activity that resulted in sucrose hydrolysis. All beverage formulations had low or no microbial growth within European limits. In conclusion, the fortification of smoothies with cardoon blades enhanced bioactive properties and quality attributes during their shelf-life, highlighting the potential of this plant material as a potential functional food ingredient in a circular economy context.

Zero-waste approach to fluoride removal by contact precipitation using Hyriopsis cumingii shells with value-added products

We propose a zero-waste approach using Hyriopsis cumingii shells for fluoride (F) removal via contact precipitation with value-added products. H3PO4 was used as the precipitant for F removal. The F concentration could be reduced from 9.5 mg/L to 0.09–0.91 mg/L for over 900 BV with running-backwashing cycle. The precipitates formed during contact precipitation were easily stripped from the shell matrix by periodic backwashing, thus supporting the continuous dissolution of calcium (Ca) from the shell particles. X-ray diffraction (XRD)-Rietveld analysis showed that the backwashing residue was fluorapatite (FAP) with a small amount of hydroxy substitution. Therefore, FAP can be used as a raw material in phosphate fertilizer manufacturing. Economic analysis and sustainability evaluation showed that the contact precipitation process with H. cumingii shells as the substrate not only reduces chemical costs but also generates value-added products; thus, this process is environmentally friendly compared to traditional methods of F removal. The proposed approach for F elimination, waste shell utilization, and F and Ca resource recovery in the contact precipitation process represents a novel sustainable water treatment technology.

Integral multi-valorization of agro-industrial wastes: A review

Agriculture and industries related to the agriculture sector generate a large amount of waste each year. These wastes are usually burned or dumped, causing damage to the environment, the economy and society. Due to their composition, they have great potential for obtaining high value-added products in biorefineries. This fact, added to the growing demand for energy and chemicals from fossil resources, is driving the interest of the scientific community in them.Biorefinery processes are hardly profitable when applied individually, so a better alternative is to develop integrated multi-feedstock and multi-product biorefinery schemes using all biomass fractions in a zero-waste approach. However, for industrial scale application, extensive research, scale-up studies, and techno-economic and environmental feasibility analyses are needed. This review compiles information on integrated multi-biorefinery processes from agro-industrial wastes to shed light on the path towards sustainable development and circular bioeconomy.

Recent Innovations on the Reuse of Almond and Hazelnut By-Products: A Review

Nuts consumption has increased significantly in the last 10 years, especially driven by the stimulated awareness of their possible beneficial health effects. Increased nuts consumption is linked to an obvious accumulation of by-products and waste. With the view of the circular economy, the aim of this review is to analyse the recent and innovative approaches able to valorise the by-products derived from almonds and hazelnuts, two important nut products of the Italian scene, with historical and traditional importance. The most important solutions are concerned with reuse of almond hull, shell, skin, oil cake, and hazelnut shell; skin and oil cake are often considered waste or by-products. Many interesting implications in the feed and food sectors have been detected in the last ten years, aimed at designing innovative materials developed from by-products and extraction of bioactive molecules for different purposes. The perspective chosen to discuss the topic is related to the sustainability of these processes, in terms of both the environment and economy. The circular economy supports a zero-waste approach, which should not also be meant as a zero-cost process in terms of the level of technology that has been partially developed.

Glasses, Frits and Glass-Ceramics: Processes and Uses in the Context of Circular Economy and Waste Vitrification

For decades, experts have paid considerable scientific and technological attention to the possibility of recycling waste that has reached nature as a result of mining activities related to natural stone, extracting metal or using foreign matter to recover natural environments. Several authors have shown that many of these types of waste can be vitrified or synthesised with an appropriately designed composition, not just to decrease their size but (as is more interesting from a financial point of view) to produce a wide range of glassy and/or ceramic materials that can have uses in industry and, crucially, in the construction sector (building and public works). In this paper, we conduct a comprehensive analysis of the state of the art, defining the different types of materials and their uses in order to decisively contribute to the circular economy and the zero-waste approach. We analyse the achievements accomplished in recent decades to be able to generate novel innovative ideas for collecting new eco-materials.

Investigation of Zero Waste Management Behavior in Turkey

&lt;p&gt;Population growth, industrialization and technological advances have significantly increased waste production, waste collection, transportation and disposal induced significant costs. Waste could be considered a resource that allows nations to reduce the consumption of primary raw materials, protect natural resources and improve economic revenues by reducing environmental pressures. Zero waste approach for sustainable waste management has been approved and implemented globally. The present study aimed to investigate the basic zero-waste management in Turkey. Thus a scale that included eight items was developed and validity and reliability of the scale were analyzed. Explanatory factor analysis (EFA) was initially applied. Then, the fitness of the model was tested with confirmatory factor analysis (CFA). Cronbach's α (internal consistency coefficient) was calculated as 0.778. Chi-square test, RMSEA, GFI and CFI fit indices were employed in the first-order confirmatory factor analysis conducted on the whole sample. Chi-square was calculated as 1.310 in confirmatory factor analysis. Also, comparative and absolute fit indices were determined as follows: RMSEA=0.035, GFI=0.976, CFI=0.987, RMR=0.030. The analysis of the findings revealed that “Zero Waste Management Behavior” scale fit indices demonstrated excellent model fit for the findings. Furthermore, there were no significant differences between one-way ANOVA and T test results on participant statements based on gender, while there were significant differences between these variables based on age, education level and the region of residence.&lt;/p&gt;&#x0D;

Effects of fermentation with different probiotics on the quality, isoflavone content, and flavor of okara beverages.

The present study aimed to prepare and evaluate a new probiotic functional beverage, using single-probiotic and compound probiotic fermentation on okara. Four different forms of fermentation microorganisms used were Lacticaseibacillus rhamnosus S24 (Lr), Lacticaseibacillus paracasei 6244 (Lp), Lactobacillus acidophilus 11,073 (La), and mixed fermentation (Lr + Lp + La). The physicochemical properties, antioxidant activity, flavor change, and storage period of fermented okara beverages with probiotics were investigated. The results showed that different fermentation schemes could significantly improve the physicochemical properties, antioxidant activity, and sensory quality of the okara beverages. The number of viable bacteria in the Lp group (3.53 × 108 CFU/mL), isoflavone content (0.514 μg/mL) were the highest; total phenol and flavonoid content were 3.32 and 5.68 times higher than in the CK group, respectively. DPPH and ABTS+ free radical scavenging rates were increased by 11.32% and 20%, respectively (p < .05). Through SPME/GC-MS analysis, 44 volatile compounds were identified in the Lr + Lp + La groups, mainly as a result of changes in alcohols and aldehydes produced by fermentation metabolism. It enhances the floral and fruity aroma of the okara beverage. All probiotic-fermented okara beverages can be stored at 4°C for 15 days, with probiotic activity greater than 107 CFU/mL. This study can obtain a probiotic okara beverage rich in soybean isoflavones and with good flavor. Overall, okara can be used to develop functional beverages containing probiotics and contribute to a zero-waste approach in the food industry.

Eisenia Fetida: A Bioremedial Worm for Sanitary Napkins and Diapers

Sanitary napkins and baby diapers are widely used around the world by menstruating women and babies. Once used, they are either dumped in landfills or incinerated which releases harmful gases such as carbon monoxide into the environment. Such material contains plastic, cotton, and synthetic substances which take hundreds of years to bio-degrade under normal conditions, hence polluting the earth's surface. The present study aims to use the earthworm species Eisenia fetida to fasten the process of biodegradation. Layers of fresh compost (which included waste materials, cow dung slurry, and water, were allowed to decompose for 15 days), cow dung, Eisenia fetida, fine compost, hay, used and unused sanitary napkins and diapers, and water were used to set up the experimental setting for degradation. The weights of the napkins and diapers initially and weekly were observed which ultimately decreased. Used diapers were set up for four to five weeks, and their weight decreased from 103g to 17.3g once every seven days, bacteria were isolated from vermicompost and the earthworms' gut by cultivating them on nutrient agar plates. Gram staining was used to further define the bacterial colonies. Gram-positive cocci, bacilli, Gram-negative rods, cocci, and bacilli containing spores and other variety in the bacterial population was seen. According to the results of the current study, vermiremediation is a very efficient, environmentally benign, and zero-waste approach for the disposal of sanitary napkins that can be used widely to reduce environmental contamination caused by them.

Pretreated Agro-Industrial Effluents as a Source of Nutrients for Tomatoes Grown in a Dual Function Hydroponic System: Tomato Quality Assessment

In a zero-waste approach for the agro-industrial sector, this study aimed to evaluate the reuse of cheese whey wastewater (chemical oxygen demand = 2.1 g L−1) pretreated by immediate one-step lime precipitation followed by natural carbonation as a nutritive solution for tomato production in hydroponic systems. Pretreated effluent, diluted with groundwater (1:6) and supplemented with nutrients, was utilized to irrigate different hydroponic systems designed to assess the influence of tomato rooting type (free/confined−setup_A) and the feed’s solution level (with/without water deep−setup_B). Plants and fruit development, fruit physicochemical characteristics and sensory analysis, and effluent quality after reuse were analyzed. Good quality tomato production with high crop yield was obtained. The highest marketable tomato weight per plant (682 g) was observed in setup_B with a deep-bed system, but setup_A, with free or confined rooting, presented similar values. The type of rooting, within setup_A or water deep within setup_B, did not significantly influence plant and fruit characteristics. The highest maturity and flavor indexes were observed for setup_A with free rooting. Regarding sensory analysis, setup_A often scored the highest in terms of overall appreciation with free or confined rooting. The reuse of cheese whey wastewater in hydroponics reduced freshwater consumption for crop production, allowed for a treated final effluent and prevented soil degradation in a sustainable circular economy methodology.

A zero-waste approach towards a sustainable waste management of apple: Extraction of value-added products and their application as edible coating

This study aimed to valorize apple pomace (AP) for the production of value-added products in a zero-waste system. A Box-Behnken design was used to optimize the microwave-assistant extraction factors on simultaneous extraction of pectin (APP) and phenolic compounds (APPC). Under optimum conditions (microwave power of 600 W, irradiation time of 6 min, liquid/solid ratio of 45, and pH of 1.5), the APP and APPC yields were 28.37 ± 1.19% and 3.42 ± 0.48%, respectively. The solid residue after co-extraction was used as a carbon source for microbial production of pullulan and single cell protein (SCP) and the maximum production yields of pullulan (43.7 g/L) and SCP (33.5%) were gained after sequential homogenization, ultrasonication and enzymatic treatment (H + U + E). The molecular weight of APP and pullulan were found to be 690.293 and 366.246 kDa, respectively. Also, the FT-IR and 1H NMR analysis confirmed the presence of pectin and pullulan in the resulting sample and their XRD pattern showed an amorphous structure. The results of DPPH, ABTS and FRAP assays indicated that the antioxidant capacity of apple pomace phenolics was comparable with vitamin C and BHA at high concentrations. Moreover, the coating with 50:50 ratios of APP and pullulan enriched with 15% APPC was selected as the best edible coating for strawberry that prolonged its shelf life until 24 days at 4 °C. The outcomes revealed that the extraction of these valuable compounds from AP in line with the sustainable agriculture development not only reduces environmental problems, but also the obtained products can be used to coat fruits.