The natural melanoidin from alcohol distillery biogester effluent and synthetic melanoidin, which was prepared in the laboratory from equimolar amounts of glucose and glycine were decolorized by Bacillus subtilis in shake flash culture. After eight days of fermentation at an initial bacterial level of 2.9 x 10 E 9 cfu/mL, natural melanoidin was 61.1 percent decolorized as measured by absorbance readings at 475 nm: the corresponding decolorization of 0.041 M synthetic melanoidin was 71.9 percent. Gel chromatography through Sephadex G-100 of natural melanoidin before and after microbial action showed molecular weight (MW) values of 35.6 and 33.5 kD, respectively; the corresponding MW values of freshly prepared and decolorized synthetic melanoidin were 42.6 and 37.7 kD, respectively. Values of the instrinsic viscosity, which is proportional to MW, of natural melanoidin before and after decolorization were 18.46 and 16.96 mL/g, respectively; corresponding viscosity values for synthetic melanoidin were 19.77 and 17.16 mL/g, respectively. After bacterial action both natural and synthetic melanoidins showed greater absorbance at 220-350 nm and lower absorbance at greater than 370 nm but showed reduced infrared intensities corresponding to C=O, C=C and O-H stretching vibrations; however the C-O infrared intensity increased. The results suggest partial depolymerization and oxidative degradation of both melanoidins caused by the microorganisms

Phytoextraction has been proposed as an alternative remediation technology for heavy metal contamination, and it is well known that chelators may alter the toxicity of heavy metals and the bioavailability in plants. Our previous work demonstrated that an adsorbent-column chromatography can effectively separate melanoidin-like product (MLP) from sugarcane molasses. The aim of this study was to examine the chelating property of MLP and to evaluate the facilitatory influence on the phytoextraction efficiency of Japanese radish. The result showed that MLP binds to all the metal ions examined and the binding capacity of MLP toward Cu²⁺ seems to be the highest among them. The metal detoxification by MLP followed the order of Pb²⁺ > Zn²⁺ > Ni²⁺ > Cu²⁺ > Fe²⁺ > Cd²⁺ > Co²⁺. Furthermore, in the phytoextraction experiment using copper sulfate, the application of MLP accelerated the detoxification of copper and the bioavailability in radish sprouts. Thus, these results suggest that MLP possesses the potential for an accelerator of phytoextraction in the copper-contaminated media.

This work aims to utilize fly ash from a thermal power station for melanoidin reduction from distillery effluent by adsorption. To accomplish this, coal fly ash was modified through chemical treatment and was then tested for melanoidin adsorption as a function of various melanoidin concentrations, contact time, and pH. The specific novelty of this study is the evaluation of coal fly ash as a low-cost adsorbent for melanoidin removal. Furthermore, the simulation study was carried out using Aspen ADSIM software in order to optimize the commercial usage of the prepared adsorbent. The main results achieved include the maximum removal efficiency of 84% which was reached at initial melanoidin concentration of 1100 mg L⁻¹ (5% dilution), pH 6, and a contact time of 120 min. The Langmuir and Freundlich isotherm models were used to evaluate adsorption isotherms. The maximum adsorption capacity of 281.34 mg/g was observed using the Langmuir isotherm. Furthermore, pseudo-first- and pseudo-second-order and intra-particle diffusion models were used to fit adsorption kinetic data. The pseudo-second-order was best describing the adsorption kinetic with a faster kinetic rate of 0.142 mg g–1 min⁻¹. CFA (coal fly ash) after acidic activation resulted in a slightly higher surface area, average pore volume, and pore size. The maximum breakthrough time and adsorbent saturation time were achieved at initial melanoidin concentration of 1 mol/lit, bed height of 2.5 m, and flow rate of 50 lit/min.

The safe disposal of post-methanated distillery sludge (PMDS) in the environment is challenging due to high concentrations of heavy metals along with other complex organic pollutants. The study has revealed that PMDS contained high amounts of Fe (2403), Zn (210), Mn (126), Cu (73.62), Cr (21.825), Pb (16.33) and Ni (13.425 mg kg⁻¹) along with melanoidins and other co-pollutants. The phytoextraction pattern in 15 potential native plants growing on sludge showed that the Blumea lacera, Parthenium hysterophorous, Setaria viridis, Chenopodium album, Cannabis sativa, Basella alba, Tricosanthes dioica, Amaranthus spinosus L., Achyranthes sp., Dhatura stramonium, Sacchrum munja and Croton bonplandianum were noted as root accumulator for Fe, Zn and Mn, while S. munja, P. hysterophorous, C. sativa, C. album, T. dioica, D. stramonium, B. lacera, B. alba, Kalanchoe pinnata and Achyranthes sp. were found as shoot accumulator for Fe. In addition, A. spinosus L. was found as shoot accumulator for Zn and Mn. Similarly, all plants found as leaf accumulator for Fe, Zn and Mn except A. spinosus L. and Ricinus communis. Further, the BCF of all tested plants were noted <1, while the TF showed >1. This revealed that metal bioavailability to plant is poor due to strong complexation of heavy metals with organic pollutants. This gives a strong evidence of hyperaccumulation for the tested metals from complex distillery waste. Furthermore, the TEM observations of root of P. hysterophorous, C. sativa, Solanum nigrum and R. communis showed formation of multi-nucleolus, multi-vacuoles and deposition of metal granules in cellular component of roots as a plant adaptation mechanism for phytoextraction of heavy metal-rich polluted site. Hence, these native plants may be used as a tool for in situ phytoremediation and eco-restoration of industrial waste-contaminated site.

This study investigates the feasibility of recovery of phosphorus via struvite precipitation from a synthetic anaerobically treated distillery spent wash by optimizing the process using a chemical equilibrium model, namely Visual MINTEQ. Process parameters such as Mg²⁺, [Formula: see text], and [Formula: see text] ion concentrations and pH were used as inputs into the model. Increasing the molar ratio of [Formula: see text] from 0.8:1 to 1.6:1 at pH 9 led to an increase in phosphate recovery from 88.2 to 99.5%. The model and experimental results were in good agreement in terms of phosphate recovery, indicating that the Visual MINTEQ model can be used to pre-determine the process parameters for struvite synthesis. Increasing the concentration of calcium ion adversely affected the synthesis and purity of struvite, whereas the presence of melanoidins had no significant impact. This study demonstrates that phosphorus recovery through struvite precipitation is a sustainable approach to reclaim phosphorus from high-strength industrial wastewater.

Coffee is perhaps one of the most vital ingredients in humans’ daily life in modern world. However, this causes the production of million tons of relevant wastes, i.e., plastic cups, aluminum capsules, coffee chaff (silver skin), and spent coffee grounds (SCG), all thrown untreated into landfills. It is estimated that 1 kg of instant coffee generates around 2 kg of wet SCG; a relatively unique organic waste stream, with little to no contamination, separated directly in the source by the coffee shops. The produced waste has been under researchers’ microscope as a useful feedstock for a number of promising applications. SCG is considered a valuable, nutrients rich source of bioactive compounds (e.g., phenolics, flavonoids, carotenoids, lipids, chlorogenic and protocatechuic acid, melanoidins, diterpenes, xanthines, vitamin precursors, etc.) and a useful resource material in other processes (e.g., soil improver and compost, heavy metals absorbent, biochar, biodiesel, pellets, cosmetics, food, and deodorization products). This paper aims to provide a holistic approach for the SCG waste management, highlighting a series of processes and applications in environmental solutions, food industry, and agricultural sector. Thus, the latest developments and approaches of SCG waste management are reviewed and discussed.