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Rising concerns over water scarcity, driven by industrialization and urbanization, necessitate the need for innovative solutions for wastewater treatment. This study focuses on developing an eco‐friendly and cost‐effective biochar‐zeolite composite (BZC) adsorbent using waste materials—spent coffee ground biochar (CGB) and steel slag zeolite (SSZ). Initially, the biochar was prepared from spent coffee ground, and zeolite was prepared from steel slag; their co‐pyrolysis resulted in novel adsorbent material. Later, the physicochemical characteristics of the BZC were examined, which showed irregular structure and well‐defined pores. Dye removal studies were conducted, which indicate that BZC adsorption reach equilibrium in 2 h, exhibiting 95% removal efficiency compared to biochar (43.33%) and zeolite (74.58%). Moreover, the removal efficiencies of the novel BZC composite toward dyes methyl orange (MO) and crystal violet (CV) were found to be 97% and 99.53%, respectively. The kinetic studies performed with the dyes and phosphate with an adsorbent dosage of 0.5 g L−1 suggest a pseudo‐second‐order model. Additionally, the reusability study of BZC proves to be effective through multiple adsorption and regeneration cycles. Initially, the phosphate removal remains high but eventually decreases from 92% to 70% in the third regeneration cycle, highlighting the robustness of the BZC. In conclusion, this study introduces a promising, cost‐effective novel BZC adsorbent derived from waste materials as a sustainable solution for wastewater treatment. Emphasizing efficiency, reusability, and potential contributions to environmentally conscious water treatment, the findings highlight the composite's significance in addressing key challenges for the removal of toxic pollutants from the aqueous solutions. Practitioner Points: A novel biochar‐zeolite composite (BZC) material has been synthesized.Excellent removal of dyes by BZC (~95%) was achieved as compared to their counterpartsThe kinetic studies performed suggest a pseudo‐second‐order model.BZC proves to be highly effective for multiple adsorption studies.Excellent reusability showed potential as a robust adsorbent [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTImpact of varying nitrate (NO3-N) and phosphate (PO4-P) concentrations and sewage water (SW) on the growth, nutrient removal, lipid accumulation, enzymatic antioxidant activity and phytochemical contents of the microalgae Scenedesmus dimorphus, Coelastrella tenuitheca, Chroococcus turgidus and Parachlorella kessleri under monoculture and their consortia have been investigated. High growth rates were observed for all the four algae in both mono and mixed culture conditions at enhanced concentrations of N (1500 mg/L NO3-N) and P (40 mg/L PO4-P). The species Scenedesmus dimorphus outperformed other microalgae growing in SW in efficiently removing nitrogen. The algal consortia of mixed species was found to be more effective in phosphorus removal. The carbohydrate and protein contents were highest in Parachlorella kessleri, about 37% and 44%, respectively, in SW cultivation. The algal consortia demonstrated highest starch content (4%) in nitrogen deprived growth medium. Highest lipid production (43%) was observed in the SW culture. The species Coelastrella tenuitheca, Chroococcus turgidus and Scenedesmus dimorphus irrespective of the growth media indicated significant accumulation of phenol, flavonoid and tannin. The DPPH, catalase and ascorbic peroxidase assay showed pronounced antioxidant activity. Nutrient (N and P) enrichment exhibited enhanced antioxidant enzymatic activity and accumulation of cell storage products.This study explores the response mechanisms and nutrient removal capabilities of various microalgal species and their consortia in sewage water treated media. The results provide valuable insights into the potential role of algae in wastewater treatment processes, revealing high tolerance and considerable NO3-N and PO4-P removal capabilities of Scenedesmus dimorphus and algal consortia toward different wastewaters. The results of the study are relevant for the development of sustainable solutions for water pollution management. The algae and their consortia grown in wastewater showed high levels of carbohydrates, proteins, lipids, bioactive compounds accumulation and antioxidant activity rendering them a sustainable and renewable resource for various industrial applications. [ABSTRACT FROM AUTHOR]

Production of potential value-added products from different lignocellulosic biomass is becoming more common due to the availability of the feedstocks in abundance and the environment- friendly nature of the microbial production process. Due to the large array of its applications in the pharmaceutical and food sectors, xylitol is considered as potential value-added compound for production. In this study, organic waste samples were collected from various habitats and screened for potential yeast isolates for xylitol production. Among 124 tested isolates, Candida tropicalis K2 showed the highest potential for xylitol production as well as inhibitors tolerance (Furfural, 5-hydroxymethyl furfural and acetic acid) phenotypes. C. tropicalis K2 produced 90 g/L of xylitol in batch fermentation (100 g/L xylose supplemented with 20 g/L of glycerol as co-substrate) with the yield and productivity of 0.90 g/g and 1.5 g/L.h, respectively, at pH 5.5 and 30°C temperature. Together, >10% higher xylitol yield was achieved when glycerol was used as a co-substrate with pure xylose. Moreover, with non-detoxified corncob and Albizia pod hydrolysates, C. tropicalis K2 isolate produced 0.62 and 0.69 g/g of xylitol yields and 1.04 and 0.75 g/L.h xylitol productivities, respectively. Thus, C. tropicalis K2 isolate could be considered as promising candidate for xylitol production from different lignocellulosic biomass. HIGHLIGHTS Candia tropicalis K2 isolate was screened from natural sites of biomass degradation and characterized for xylitol production. Non-detoxified Albizia pod and corncob hydrolysates were explored for xylitol production using selected C. tropicalis K2 isolate. A maximum of 0.90 g/g yield and 1.07 g/L.h xylitol productivity was achieved with pure xylose. A >10% increase in xylitol yield was achieved using glycerol as a co-substrate. [ABSTRACT FROM AUTHOR]

Essential oils are becoming highly valued these days because of their practicality, therapeutic efficacy, safety, and food preservation qualities, as well as their overall health benefits. The negative consequences of synthetic preservatives in food, cosmetics, and medications are becoming more widely known. Therapeutic plants are abundant sources of essential oils which are secondary metabolites and volatile in nature. Plant materials such as fruit peels, bark, seeds, flowers, roots, leaves, and wood are used to make essential oils. Some important examples include cinnamon, eucalyptus, thyme, eucalyptus, oregano, clove, basil, lemon, rosemary, and ginger. They have potent antibacterial and foodpreservation properties. They contain several active compounds, including terpenes, terpenoids, carotenoids, and curcumin. Especially in the sanitary, cosmetic, food, pharmaceutical and agricultural industries, essential oils are frequently employed for antiviral, insecticidal, fungicidal, bacterial, antiparasitic, medicinal, or cosmetic uses. Different conventional techniques are employed to extract the oils, including ultrasound-assisted extraction, supercritical fluid extraction, microwave-assisted extraction. Due to their nontoxic properties and numerous health benefits, essential oils as natural preservatives have an advantage over their synthetic counterparts. This review focuses on how essential oils work as food preservatives. [ABSTRACT FROM AUTHOR]

In this study, paper mill wastewater and hemicellulose hydrolysate were evaluated as low-cost substrates for fungal chitosan production using Penicillium citrinum. Submerged fermentation was first studied using a bioreactor operated under batch, fed-batch and continuous modes with paper mill wastewater as the substrate. Very high removal (91%) of organics as chemical oxygen demand (COD) in the wastewater with 160 mg L-1 chitosan production by P. citrinum was obtained using the bioreactor operated under fed-batch mode for 72 h. Moreover, 86% reduction of phenolics in the wastewater with 89% decolourization efficiency was achieved in the fed-batch experiments with the bioreactor. Under the continuous mode of operation with the bioreactor, maximum chitosan production of 170 mg L-1 was observed. The effect of acetic acid addition to the wastewater for enhancing chitosan production by the fungus was further studied in a batch system. Chitosan productivity of 2.33 mg L-1 h-1 was obtained with 50 mg/L acetic acid. Various models, viz. Monod, Haldane, Andrews, Webb and Yano, were fitted to the experimental data for understanding the kinetics involved in the process. Haldane model accurately fitted the experimental data on biomass specific growth rate, acetic acid consumption rate and chitosan production rate by P. citrinum with acetic acid addition to the wastewater. Fungal fermentation of another low-cost substrate, rice straw hydrolysate, was further studied using the batch-operated bioreactor; and a maximum chitosan titre of 911 mg L−1 was achieved using the detoxified rice straw hydrolysate. Highlights Low-cost substrates for chitosan production by Penicillium citrinum are reported Acetic acid addition to paper mill wastewater enhances chitosan production Biomass growth and chitosan production follow substrate inhibition kinetics Fed-batch -operated bioreactor resulted in 91% wastewater treatment efficiency Maximum chitosan titre of 911 mg L−1 was achieved with rice straw hydrolysate [ABSTRACT FROM AUTHOR]

The urge for alternative forms of energy to meet the demands of the ever-growing population is a primary concern throughout the world. With the improvement in technologies, biomass seems to be a potential feedstock for conversion to bio-oil by either pyrolysis or hydrothermal liquefaction (HTL). The latter is advantageous as wet biomass can be used directly without any pretreatment, and HTL also produces useful byproducts along with bio-oil. The use of oleaginous microorganisms such as algae, bacteria, and yeasts as biomass feedstocks for the HTL process is more beneficial compared to other conventionally used feedstocks such as lignocellulosic biomass, owing to their high oil content and fast growth rate even on cheaply available substrates. This paper provides an insight into the advantages and detailed information on different oleaginous microorganisms, their composition, and the use of wastewater as their substrate for cultivation. It also emphasizes HTL as an appropriate thermochemical conversion process for biomass processing and production of bio-oil as well as the different process parameters affecting the HTL technology. An integrated HTL based sustainable biorefinery approach for resource recovery in the form of energy is also discussed in detail, along with the future research perspectives in this field. [ABSTRACT FROM AUTHOR]