Organic Waste Research Articles

Assessment of the surface water quality and primary health risk in urban wastewater and its receiving river Kathajodi, Cuttack of eastern India.

Kathajodi, the principal southern distributary of the Mahanadi River, is the vital source of irrigation and domestic water use for densely populated Cuttack city which receives anthropogenic wastes abundantly. This study assesses the contamination level and primary health status of urban wastewater, and its receiving river Kathajodi based on the physicochemical quality indices employing inductively coupled plasma mass spectroscopy and aligning with guidelines from the United States Environmental Protection Agency (USEPA) and WHO. The high WQI, HPI, and HEI in the catchment area (KJ2, KJ3, and KJ4) indicate poor water quality due to the influx of domestic waste through the primary drainage system and effluents of healthcare units. A high BOD (4.33-19.66mg L-1) in the catchment indicates high organic matter, animal waste, bacteriological contamination, and low DO, resulting in deterioration of water quality. CR values beyond limits (1.00E - 06 to 1.00E - 04) in three locations of catchment due to higher Cd, Pb, and As indicate significant carcinogenic risk, while high Mn, Cu, and Al content is responsible for several non-carcinogenic ailments and arsenic-induced physiological disorders. The elevated heavy metals Cd, Cu, Fe, Mn, Ni, and Zn, in Kathajodi, could be due to heavy coal combustion, vehicle exhaust, and industrial waste. On the other hand, Cu, Fe, K, and Al could be from agricultural practices, weathered rocks, and crustal materials. Positive significant (p ≤ 0.05) Pearson correlations between physicochemical parameters indicate their common anthropogenic origin and similar chemical characteristics. A strong correlation of PCA between elements and physiological parameters indicates their role in water quality deterioration. Assessing the surface water quality and heavy metal contents from this study will offer critical data to policymakers for monitoring and managing public health concerns.

Characteristics and management of municipal solid waste in Uyo, Akwa Ibom state, Nigeria

Increased urbanization and population lead to increased consumption of manufactured goods. This ultimately results in increased production of waste. Identifying its composition is crucial for planning an effective solid waste management strategy. This study assesses the characteristics and composition of the waste generated within the Uyo Capital City Development Area of Akwa Ibom State, Nigeria. This is to aid in developing a scientifically supported waste management pilot system for the state. Direct waste sorting and characterization were conducted on the municipal solid waste arriving at the landfill during the study period. Over 50% of the generated wastes are recyclables and composed of plastics, metals, and paper, while the fraction of organic waste is over 30%. Similarly, the waste generation per capita is 1.34 kg/person/day, while the generation forecast over the next ten years is estimated to increase by approximately 40%. Furthermore, over 9,000 surveys were completed by residents to establish a problem statement about the existing waste collection and disposal system, and possible solutions. Importantly, a majority of survey respondents were willing to source-separate their wastes and supported paying a fee for adequate waste collection. This strongly indicates that an integrated waste management system could be established to generate value from the collected waste. Supplementary revenue can be generated through composting, recycling, and land reclamation.

Utilization of plant-derived wastes as the potential biohydrogen source: a sustainable strategy for waste management.

The sustainable economy has shown a renewed interest in acquiring access to the resources required to promote innovative practices that favor recycling and the reuse of existing, unconsidered things over newly produced ones. The production of biohydrogen through dark anaerobic fermentation of organic wastes is one of the intriguing possibilities for replacing fossil-based fuels through the circular economy. At present, plant-derived waste from the agro-based industry is the main global concern. When these wastes are improperly disposed of in landfills, they become the habitat for several pathogens. Additionally, it contaminates surface water as a result of runoff, and the leachate that is created from the waste enters groundwater and degrades its quality. However, cellulose and hemicellulose-rich plant wastes from agriculture fields and agro-based industries have been employed as the most efficient feedstock since carbohydrates are the primary substrate for the synthesis of biohydrogen. To produce biohydrogen from plant-derived wastes on a large scale, it is necessary to explore comprehensive knowledge of lab-scale parameters and pretreatment strategies. This paper summarizes the problems associated with the improper management of plant-derived wastes and discusses the recent developments in dark fermentation and substrate pretreatment techniques with the goal of gaining significant insight into the biohydrogen production process. It also highlights the utilization of anaerobic digestate, which is left over after biohydrogen gas as feedstock for the development of value-added products such as volatile fatty acids (VFA), biochar, and biofertilizer.

Decomposing Unit for Agricultural Waste

The decomposer unit is an essential part of the process that turns organic waste and raw materials into fertilizers, which makes a big difference in waste management and sustainable farming methods. This unit takes raw materials, mostly organic waste, and starts a sequence of actions to turn them into fertilizer that can be used. Organic matter breaks down chemically during decomposition, producing simpler chemicals that are high in potassium, phosphate, and nitrogen—three important nutrients. For the purpose of increasing soil fertility and fostering plant growth, these nutrients are essential. This process is optimized by the decomposer unit, which guarantees effective raw material usage and reduces waste

WEBINAR SEBAGAI SARANA SOSIALISASI PENGOLAHAN LIMBAH ORGANIK MENJADI EKO-ENZIM

Organic waste resulting from anthropogenic and industrial activities has become a source of pollution that can disrupt the existence of the environment. Various efforts have been made to minimize the presence of these sources of pollution, including processing them into more useful products. Eco-enzymes are a product that can be produced from organic waste which is processed through an anaerobic fermentation process. This online community service activity packaged through a webinar aims to be a means of communication and socialization media to raise public awareness about the urgency of managing organic waste as well and provide new insights in processing organic waste into more useful products in the form of eco-enzymes. The method used was participatory through an online seminar involving 144 participants from various backgrounds of regional, scientific disciplines, professions, and social status. The results of this activity show that there is enthusiasm among the participants in discussions regarding the use and processing of organic waste into eco-enzymes. This webinar is also able to build good communication and interpersonal interaction patterns, discussion and elaboration of material becomes more constructive, and reaches many participants from various regions, scientific disciplines, professions, and social status.

Screening of enhanced biohydrogen production from anaerobic fermentation amended with nano-sized barium ferrite supported by aluminum oxide

Anaerobic fermentation has attracted wide attention to effectively reduce carbon footprint and alleviate potential energy shortages, which is being regarded as a sustainable and promising technology to obtain high biohydrogen production from widespread organic wastes. However, biohydrogen commercial uptake is now dominantly inhibited by the low hydrogen yield and process instability. In this work, Al2O3/BaFe2O4 nanoparticles (NPs) are successfully applied to anaerobic fermentation for investigating their effects on hydrogen yield, activity of bacteria and microbial community structure. The benefits of Al2O3/BaFe2O4 NPs with respect to microbial metabolism, reactivity of enzymes and process optimization are systematically researched through batch experiments. In addition, various characterizations are used to verify the physical and chemical properties of Al2O3/BaFe2O4 NPs. The results show that the activity of hydrogenases and microbe metabolism can be significantly inhibited by excess addition of Al2O3/BaFe2O4 NPs (150 mg/L and 200 mg/L) while the optimum addition 100 mg/L of Al2O3/BaFe2O4 NPs can boost the biohydrogen yield by 49% via facilitating microorganism growth and enhancing key enzymatic activities, which indicate that the Al2O3/BaFe2O4 NPs display a beneficial influence on electron transfer efficiency and process stability. The existence of Fe3+, Al3+and Ba2+ derived from the corrosion of Al2O3/BaFe2O4 NPs by organic acids synergistically improve the microbial transmembrane transportation and substrate utilization, which contribute to higher conversion rate of glucose into acetate, butyrate and H2. Meanwhile, the complementary functions of Fe3+ and Al3+ can powerfully shorten the lag phase and promote the glycolysis, which finally accelerate the dark fermentation process. Compared with the control group, Clostridium_sensu_stricto_1 is selectively enriched by the addition of Al2O3/BaFe2O4 NPs, which keep heavily involved in the synthesis of H2. On balance, this study provides an effective strategy to enhance hydrogen productivity and maintain process stability, which offer the valuable information for the sustainable utilization of sewage sludge.

Bioactive Compounds from Organic Waste

The reuse and reincorporation of waste are the principles of circular economies. Compost, biofuels, animal feed, dyes, and bioactive compounds can be obtained from the revaluation of organic waste. Research on this subject is scarce and limited to specific sectors, such as agriculture and agroindustry, leaving aside others that generate large quantities of organic waste, such as floriculture. The remains of these sectors have a low decomposition rate compared to other organic wastes. They are a source of bioactive compounds (e.g., essential oils, pigments, phenols) that can be reincorporated into the production chain of various industries. This review describes the composition of waste from agroindustry, agriculture, and floriculture, analyzing their potential revalorization as a source of bioactive compounds and an alternative supply source.

Impacts of free nitrous acid on stabilizing food waste and sewage sludge for anaerobic digestion

This work investigated the effectiveness of free nitrous acid (FNA) in enhancing organic waste solubilization to improve biogas production in anaerobic digestion (AD). The results indicated that FNA pretreatment can enhance soluble organic content and control H2S odor in tested organic wastes, including food waste, sewage sludge, and their combination. However, a significant decrease (>50 %) in FNA concentration was found in the reactors, possibly due to denitrifier-driven NO2– consumption. Biochemical methane potential (BMP) tests showed a 25 ± 8 % enhancement in CH4 production in the reactors fed with mixed substrate pretreated with 2.9 mg FNA-N/L. However, the presence of NO2– (325.6–2368.0 mg N/L) in some BMP reactors, due to carryover from FNA pretreatment, adversely affected CH4 production (>55 %) and prolonged lag time (>4.2 times). These findings are valuable for researchers and practitioners in waste management, offering insights for implementing FNA pretreatment to enhance the biodegradability of organic wastes in AD.

Fungal mycelium-based biofoam composite: A review in growth, properties and application

Recent years have shown a surge in interest in incorporating living systems into materials research to synthesize functional materials using biological resources. Among these, mycelium-based materials, notably biofoam, have emerged as innovative solutions for repurposing organic wastes that were previously considered unusable. The growth of mycelium, vital for the synthesis of biofoam, is influenced by a multuple of factors including substrate composition, moisture content, temperature, nutrient availability, pH levels, oxygen concentration, and measures for contamination control. Additionally, physical stimulation techniques have been explored to enhance mycelium growth, ranging from cold stress-induced adaptations to electrical shock-induced modifications and optimization of sound treatments and light exposure. This review highlights the growing interest in biofoam composite materials, a novel class of environmentally friendly and cost-effective materials that are gaining popularity, for advancing sustainable construction practices. Biofoam composites use organic fungal growth as a low-energy bio-fabrication process to transform abundant agricultural byproducts and waste into viable alternatives to energy-intensive manufactured building materials. Their versatility in composition and manufacturing methods allows them to be used in a wide range of applications, including insulation and door cores, panelling, flooring, and furniture components. Notably, biofoams outperform synthetic foams and engineered wood in terms of thermal insulation, sound absorption, and fire resistance, making them highly promising for construction industry. Besides, due to its customizable composition and production method, biofoam can be used in the replacement of foams, leather, wood, and plastics in a variety of applications such as water treatment and filtration, medical supplies and healthcare applications. However, despite their remarkable properties, biofoam typically serve as non- or semi-structural supplements to traditional construction materials due to inherent limitations. Nevertheless, the useful material properties of these materials, combined with their low cost, ease of manufacture, and environmental sustainability, imply that they will have an important part to play in the development of environmentally friendly materials in the future.

Enhancing biomethanation performance through co-digestion of diverse organic wastes: a comprehensive study on substrate optimization, inoculum selection, and microbial community analysis.

A blend of organic municipal solid waste, slaughterhouse waste, fecal sludge, and landfill leachate was selected in different mixing ratios to formulate the best substrate mixture for biomethanation. Individual substrates were characterized, and the mixing ratio was optimized with the help of a response surface methodology tool to a value of 1:1:1:1 (with a C/N ratio of 28±0.769 and total volatile fatty acid (VFA) concentration of 2500±10.53 mg/L) to improve the overall biomethanation. The optimized blend (C/N ratio: 28.6, VFA: 2538 mg/L) was characterized for physicochemical, biological, and microbial properties and subjected to anaerobic digestion in lab-scale reactors of 1000 mL capacity with and without the addition of inoculum. The biogas yield of individual substrates and blends was ascertained separately. The observed cumulative biogas yield over 21 days from the non-inoculated substrates varied between 142±1.95 mL (24.6±0.3 ml/gVS) and 1974.5±21.72 mL (270.4±3.1 ml/gVS). In comparison, the addition of external inoculation at a 5% rate (w/w) of the substrate uplifted the minimum and maximum cumulative gas yield values to 203±9.9 mL (35.0±1.6 mL/gVS) and 3394±13.4 mL (315.3±1.2 mL/gVS), respectively. The inoculum procured from the Defence Research and Development Organisation (DRDO) was screened in advance, considering factors such as maximizing VFA production and consumption rate, biogas yield, and digestate quality. A similar outcome regarding biogas yield and digestate quality was observed for the equivalent blend. The cumulative gas yield increased from 2673±14.5 mL (373.7±2.2 mL/gVS) to 4284±111.02 mL (391.47±20.02 mL/gVS) over 21 days post-application of a similar dosage of DRDO inoculum. The 16S rRNA genomic analysis revealed that the predominant bacterial population belonged to the phylum Firmicutes, with the majority falling within the orders Clostridiales and Lactobacillales. Ultimately, the study advocates the potential of the blend mentioned above for biomethanation and concomitant enrichment of both biogas yield and digestate quality.

Design and optimization of a novel intestinal reactor to efficiently improve organic waste uniformity and solid content in high solid organic waste anaerobic digestion

High solid anaerobic digestion (HSAD) technology, a major treatment method for solid organic waste. Existing HSAD reactors comprise primarily vertical and horizontal reactors. Vertical reactors use high-pressure pneumatic stirring, which has high energy consumption and poor stirring performance. Horizontal reactors use long-uniaxial mechanical stirring, which occupies large land areas and has high strength requirements for stirring shaft material. In addition, during the operation of the two reactor types, the continuous liquefaction of the solid waste produces solid-liquid stratification, thus affecting mixing effects and decreasing the reactor volume rate. To solve the above problems, we designed a new simulated intestinal anaerobic digestion reactor with a natural solid-liquid separation system, short-axis mechanical stirring, and a stirring blade optimized through CFD. Use of the solid-liquid separation system increased the solid content in the reactor by 44%–55%. The operation results indicated that the homogenization of the solid waste with the optimal stirring blade was more than 50% greater than that of a conventional vertical reactor. The intestinal reactor solves the problems of poor uniformity and solid content decrease during anaerobic digestion in traditional HSAD, decreases the strength requirements for stirring shaft material, and has potential to increase urban waste treatment capacity.

Evaluating the efficacy of vermicomposted products in rain-fed wetland rice and predicting potential hazards from metal-contaminated tannery sludge using novel machine learning tactic

The study assessed the ecotoxicity and bioavailability of potential metals (PMs) from tannery waste sludge, alongside addressing the environmental concerns of overuse of chemical fertilizers, by comparing the impacts of organic vermicomposted tannery waste, chemical fertilizers, and sole application of tannery waste on soil and rice (Oryza sativa L.) plants. The results revealed that T3, which received high-quality vermicomposted tannery waste as an amendment, exhibited superior enzymatic characteristics compared to tannery sludge amended (TWS) treatments (T8, T9). After harvesting, vermicomposted tannery waste treatment (T3) showed a more significant decrease in PMs bioavailability. Accumulation of PMs in rice was minimal across all treatments except T8 and T9, where toxic tannery waste was present, resulting in a high-risk classification (class 5 < 0.01) according to the SAMOE risk assessment. Results from Fuzzy-TOPSIS, ANN, and Sobol sensitivity analyses (SSA) further indicated that elevated concentrations of PMs (Ni, Pb, Cr, Cu) adversely impacted soil-plant health synergy, with T3 showing a minimal risk in comparison to T8 and T9. According to SSA, microbial biomass carbon and acid phosphatase activity were the most sensitive factors affected by PMs concentrations in TWS. The results from the ANN assay revealed that the primary contributing factor of toxicity on the TWS was the exchangeable fraction of Cr. Correlation statistics underscored the significant detrimental effect of PMs' bioavailability on microbial and enzymatic parameters. Overall, the findings suggest that vermicomposting of tannery sludge waste shows potential as a viable organic amendment option in the near future.

Evaluating the Environmental Impacts of Pretreatment and Nanoparticles in Solid-State Anaerobic Digestion Using Life Cycle Assessment

AbstractThe yield of green energy from solid-state anaerobic co-digestion (SSAD) has recently been enhanced by incorporating innovative pretreatment methods and nanoparticles. However, the environmental consequences of employing new processes have not been fully examined. In this study, the environmental impacts of three high-methane-yielding scenarios including SSAD of corn stover blended with dairy manure (DM) denoted as (SYM1), calcium hydroxide-pretreated corn stover (CpCS) blended with DM (SYM2), and the CpCS blended with DM and nanoparticles (SYM3) were assessed and compared the baselines of solid-state and semi-solid-state anaerobic digestion using a life cycle assessment (LCA) approach. The approach investigated the best management practices that would result in high methane yield and low environmental impact. Results of the life cycle assessment indicate the inclusion of calcium hydroxide and nanoparticle has minimal negative environmental impact. There was an environmental gain in GWP when corn stover was co-digestion with DM (SYM1) relative to DM mono-digestions (baselines) and the carbon footprint of SYM1 was less by more than 85% compared to SYM2 and SYM3. However, the large volume of untreated corn stover harnessed for SYM1 scenario resulted in over 75% fossil fuel depletion compared to the other scenarios. The surplus methane from the SYM3 (at least twofold of other scenarios and baselines) in conjunction with being the least with the environmental implication makes the scenario the most attractive option for on-farm practice capable of harnessing the growing organic waste volume. These outcomes can guide trade-off between pretreatment and nanoparticle application to reduce solid-state anaerobic digestion’s negative environmental impact.

A novel approach to assessing the anaerobic bio-accessibility of straw using fractal dimension

Traditional methods for evaluating the bioconversion capacity of organic solid waste are known for time-consuming property and often exhibit low prediction accuracy. However, leveraging fractal dimensions offers a more precise characterization of the complexity, irregularity, and spatial structure of organic solid waste. In this study, a novel and efficient method for evaluating the bio-accessibility of straw's anaerobic transformation, based on fractal dimensions, was introduced. To comprehensively compare the structural differences, this research encompasses the measurement of nine different varieties of straw under ten distinct pretreatment conditions. The regression sum of squares for these correlations consistently exceeds 0.83, highlighting the robustness of our findings. The results unequivocally demonstrate the close relationship between the fractal dimension and the structural characteristics of straw. This relationship underscores the utility of fractal dimension analysis as a reliable tool for evaluating the anaerobic bio-accessibility of organic solid waste.

Organic Fertilizer in Medicinal and Aromatic Plant Production: SWOT Analysis and Strategies

Medicinal and aromatic plants have been used for centuries for food, medicine, cosmetics, and spices. Due to increasing human and environmental health problems, interest in organic products is increasing day by day. The use of organic fertilizers not only improves crop quality but also improves soil and utilizes waste. The aim of the study is to conduct a SWOT analysis of the use of organic fertilizers in medicinal and aromatic plant production and to identify strategies. The SWOT analysis showed that strengths and opportunities outnumbered weaknesses and threats. Strategies (SO, ST, SW, WO, WT, WT, OT) were identified. Weaknesses and threats can be reduced by government incentives and training. The most notable weakness is that the use of organic fertilizers leads to low yields. Someone who aims to produce not only yield-based but also quality-based products should use organic fertilizers instead of chemical fertilizers. Organic fertilizer produces healthy, quality crops, improves the physical, chemical and biological properties of the soil and, if produced from organic waste, reduces environmental pollution and the amount of waste to be managed. The state should further promote the use of organic fertilizer to protect human and environmental health and to increase domestic/foreign markets. Producers should be trained in the effective production and use of organic fertilizer.

Counseling on the Use of Organic Waste in Realizing Sustainable Development in Villages

Desa Biringala merupakan salah satu desa yang berada di Kecamatan Barombong, Kabupaten Gowa, Sulawesi Selatan. Secara geografis letak Desa Biringala sangat strategis karena Desa Biringala merupakan salah satu desa penopang Kawasan Ekonomi di Kabupaten Gowa Sulawesi Selatan. Permasalahan yang saat ini dihadapi oleh desa Biringala adalah permasalahan lingkungan hidup, hal ini disebabkan karena masih kurangnya kesadaran masyarakat terhadap pengelolaan sampah, selain itu sarana prasarana seperti armada pengangkut sampah serta TPA (Tempat Pembuangan Akhir) dan TPS (Tempat Pembuangan Sampah) masih belum ada. sangat terbatas. Untuk mengatasi permasalahan tersebut, salah satu alternatif solusi yang dapat diterapkan adalah dengan mengadakan kegiatan pengelolaan pemanfaatan sampah organik dalam mewujudkan pembangunan berkelanjutan di Desa Biringala, Kecamatan Barombong, Kabupaten Sulawesi Selatan. Oleh karena itu, tujuan dari pengabdian masyarakat ini adalah untuk melihat potensi pemanfaatan sampah organik dalam mewujudkan pembangunan berkelanjutan di Desa Biringala, Kecamatan Barombong, Sulawesi Selatan. Untuk memperoleh data yang digunakan adalah observasi dan studi pustaka. Kegiatan pengabdian ini merupakan upaya edukasi pemanfaatan sampah organik di Desa Biringala, Kecamatan Barombong, Kabupaten Gowa, Sulawesi Selatan. Sebagai bentuk pemikiran penulis, maka ditawarkan beberapa upaya dan terobosan, yaitu: 1.) Meningkatkan pengetahuan dan pendapatan masyarakat yang telah mengetahui bahwa sampah organik dapat dimanfaatkan sehingga dapat menciptakan kesejahteraan masyarakat yang berkelanjutan, 2.) Peran serta pemanfaatan sampah organik bagi masyarakat Desa Biringala dalam mewujudkan pembangunan desa berkelanjutan adalah untuk meningkatkan kualitas hidup menjadi lebih bersih dan Sehat.

Recent advancements in harnessing biodiesel from microalgae through attached growth systems

Conventional microalgal cultivation method relied on suspended growth or attached growth that uses inert solid surfaces, requiring the addition of external carbon sources to promote microalgal growth. The inert solid substrates for attached microalgae pose constraints on the maximal capabilities of these microorganisms as it does not possess the ability to provide the necessary nutritional support required for optimal microalgal growth. As a result, microalgae are obliged to only rely on the solid substrate as a means of attachment, without any further nutritional provisions. Slower growth rates, larger resource requirements, and exorbitant operating expenses had prompted the exploration of an alternative strategy, i.e; the innovative use of solid organic waste as nutritional source cum attachment platform. The findings of this review unveil key insights into microalgae cultivation system, offering a solution to economic challenges in the production phase. This innovation not only promotes economic feasibility and sustainability, but also contributes to economically viable and environmentally sustainable biofuel production.

Synthesis of Material Composite rGO-TIO2 From Coconut Shells by Sol-Gel Methods as Photocatalyst

&lt;p&gt;The rGO- TiO&lt;sub&gt;2&lt;/sub&gt; composite photocatalyst is receiving great attention because of its high performance. But the study of rGO- TiO&lt;sub&gt;2&lt;/sub&gt; composite with sources of rGO material derived from the utilization of organic waste such as coconut shells is limited. In this study, the synthesis of nanocomposite rGO- TiO&lt;sub&gt;2&lt;/sub&gt; was described with rGO obtained from coconut shells. The rGO samples produce through the oxidation and reduction process. The transformation of graphene oxide into reduced graphene oxide was assisted by microwave irradiation. The obtained rGO was then composite with Titanium tetraisopropoxide (TTIP) by the sol-gel method. The composite of rGO- TiO&lt;sub&gt;2&lt;/sub&gt; was characterized by XRD, FTIR, UV-Vis, and SEM. The photocatalytic performance of the rGO- TiO&lt;sub&gt;2&lt;/sub&gt; composite was conducted on Methylene blue. The result shows that rGO- TiO&lt;sub&gt;2&lt;/sub&gt;composite has a good photocatalytic performance with the highest number at 96%.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;

Approaches for Enhancing Wastewater Treatment of Photocatalytic Fuel Cells: A Review.

Environmental pollution and energy crises have garnered global attention. The substantial discharge of organic waste into water bodies has led to profound environmental contamination. Photocatalytic fuel cells (PFCs) enabling the simultaneous removal of refractory contaminants and recovery of the chemical energy contained in organic pollutants provides a potential strategy to solve environmental issues and the energy crisis. This review will discuss the fundamentals, working principle, and configuration development of PFCs and photocatalytic microbial fuel cells (PMFCs). We particularly focus on the strategies for improving the wastewater treatment performance of PFCs/PMFCs in terms of coupled advanced oxidation processes, the rational design of high-efficiency electrodes, and the strengthening of the mass transfer process. The significant potential of PFCs/PMFCs in various fields is further discussed in detail. This review is intended to provide some guidance for the better implementation and widespread adoption of PFC wastewater treatment technologies.

Utilizing chitooligosaccharides from shrimp waste biodegradation via recombinant chitinase A: a promising approach for emulsifying hydrocarbon and bioremediation

BackgroundHydrocarbon pollution stemming from petrochemical activities is a significant global environmental concern. Bioremediation, employing microbial chitinase-based bioproducts to detoxify or remove contaminants, presents an intriguing solution for addressing hydrocarbon pollution. Chitooligosaccharides, a product of chitin degradation by chitinase enzymes, emerge as key components in this process. Utilizing chitinaceous wastes as a cost-effective substrate, microbial chitinase can be harnessed to produce Chitooligosaccharides. This investigation explores two strategies to enhance chitinase productivity, firstly, statistical optimization by the Plackett Burman design approach to  evaluating the influence of individual physical and chemical parameters on chitinase production, Followed by  response surface methodology (RSM) which delvs  into the interactions among these factors to optimize chitinase production. Second, to further boost chitinase production, we employed heterologous expression of the chitinase-encoding gene in E. coli BL21(DE3) using a suitable vector. Enhancing chitinase activity not only boosts productivity but also augments the production of Chitooligosaccharides, which are found to be used as emulsifiers.ResultsIn this study, we focused on optimizing the production of chitinase A from S. marcescens using the Plackett Burman design and response surface methods. This approach led to achieving a maximum activity of 78.65 U/mL. Subsequently, we cloned and expressed the gene responsible for chitinase A in E. coli BL21(DE3). The gene sequence, named SmChiA, spans 1692 base pairs, encoding 563 amino acids with a molecular weight of approximately 58 kDa. This sequence has been deposited in the NCBI GenBank under the accession number "OR643436". The purified recombinant chitinase exhibited a remarkable activity of 228.085 U/mL, with optimal conditions at a pH of 5.5 and a temperature of 65 °C. This activity was 2.9 times higher than that of the optimized enzyme. We then employed the recombinant chitinase A to effectively hydrolyze shrimp waste, yielding chitooligosaccharides (COS) at a rate of 33% of the substrate. The structure of the COS was confirmed through NMR and mass spectrometry analyses. Moreover, the COS demonstrated its utility by forming stable emulsions with various hydrocarbons. Its emulsification index remained stable across a wide range of salinity, pH, and temperature conditions. We further observed that the COS facilitated the recovery of motor oil, burned motor oil, and aniline from polluted sand. Gravimetric assessment of residual hydrocarbons showed a correlation with FTIR analyses, indicating the efficacy of COS in remediation efforts.ConclusionsThe recombinant chitinase holds significant promise for the biological conversion of chitinaceous wastes into chitooligosaccharides (COS), which proved its potential in bioremediation efforts targeting hydrocarbon-contaminated sand.