Investigation of biotransformation and biosorption properties of cladosporium cladosporioides mold

Chalcones possess an organic structure and are chemically characterized by a distinctive alpha, beta-unsaturated ketone backbone, and phenyl rings appended to this chain. Frequently encountered in the plant kingdom, these structures undertake diverse essential roles in their host plants' vital chemical processes (metabolism) and ecological interactions. As members of the flavonoid class, chalcones are renowned for exhibiting various biological activities, including antioxidant, antimicrobial, antitumor, and anti-inflammatory properties. Owing to these biological effects, they are subjects of intense scientific interest regarding their potential positive impacts on human health and their prospective applications in the pharmaceutical industry. Furthermore, they are involved in vital plant functions, such as forming pigments and defense mechanisms against diseases, and predominantly accumulate in the flowers, fruits, and leaves. These compounds can be obtained naturally, through direct isolation from plants, or synthesized artificially in the laboratory via chemical reactions. Specifically, synthesized chalcone derivatives offer valuable tools for drug development initiatives and fundamental scientific research to elucidate the structure-activity relationships, reveal mechanisms of action, and design novel therapeutic agents. Consequently, employing the metabolic power of microorganisms to improve or diversify the structure and function of natural substances is regarded as a pathway with significant potential for both scientific advancement and industrial innovation. Environmental pollution remains a globally significant and prioritized issue. The increase in the world's population, coupled with escalating consumption demands, has accelerated industrial production processes. In the context of Turkey, the textile industry constitutes one of the principal industrial sectors underpinning the national economy, exhibiting a notable concentration, particularly in the Marmara Region. Foremost among the environmental impacts of this sector is the industrial wastewater generated as a consequence of production processes, which contain high concentrations of dyestuffs. Treating such wastewater through appropriate purification processes before its discharge into receiving water bodies is a legal and environmental imperative. Nevertheless, the substantial investment and operational costs associated with industrial wastewater treatment plants lead many enterprises to operate these systems below full capacity or to take them out of service. This situation underscores the necessity for developing innovative and economically efficient treatment technologies to optimize treatment costs. Among the principal technologies currently applied for treating dye-containing wastewater are electrochemical methods, adsorption processes, and various physical filtration techniques. While electrochemical treatment offers high efficiency, it represents a comparatively costly alternative due to its energy consumption. Physical filtration applications may not always ensure the targeted level of purification. Adsorption processes are widely favored and stand out as a practical approach due to several advantages, such as the generally low cost of adsorbent materials, high process efficiency, operational simplicity, and the potential for integration with other techniques (e.g., filtration). In adsorption processes, alongside naturally available adsorbents like clay minerals, materials endowed with adsorbent properties through various physicochemical treatments can also be utilized. The selection of an ideal adsorbent for a given process is based on criteria such as low cost, ready availability, high adsorption capacity, physical and chemical stability under process conditions, avoidance of secondary pollution through dissolution during treatment, and the potential for reuse after regeneration. In this framework, fungal biomass (particularly molds) emerges as a potential biomaterial that fulfills a significant portion of the specified adsorbent criteria. The ability to regenerate them from spores stored under suitable conditions post-isolation constitutes a considerable advantage that reduces biomass production costs. Additionally, obtaining large quantities of biomass through the rapid and straightforward proliferation of fungal spores in specific nutrient media is feasible. The treatment process employing fungal biomass as an adsorbent is defined in the literature as "biosorption," owing to a biologically derived material. To explain the removal processes conducted with fungal biomass through adsorptive mechanisms, the biomass is generally subjected to inactivation following its proliferation phase. Various functional groups in inactive fungal cell walls, such as carboxyl, amine, and phosphate groups, assume a central role in the adsorption process. These groups can undergo ionization depending on the pH conditions of the medium and facilitate the binding of dye molecules to the biomass surface by forming electrostatic attractions, hydrogen bonds, or other weak interactions with complementary or oppositely charged functional groups present in the dye molecules within the wastewater. Wastewaters from the textile industry typically contain a complex composition of dyes belonging to different chemical classes rather than a single type of dyestuff. This heterogeneous chemical nature of wastewater presents technical difficulties in determining the concentration of each dye component. However, conducting these individual analyses is critically necessary to accurately evaluate the performance of the applied treatment process and the removal efficiency specific to each dyestuff. While chromatographic methods (e.g., HPLC) can be employed to separate and analyze components in such complex mixtures, these techniques generally necessitate high-cost instrumentation, specialized consumables, and relatively long analysis times. A more practical and common method, standard spectrophotometric analysis, allows for determining the concentration of pure dye solutions by measuring their absorbance values at characteristic wavelengths. However, in dye mixtures, the overlap of the absorbance spectra of different components renders the direct application of this standard method and the acquisition of accurate results impossible. Derivative spectrophotometry techniques have been developed to overcome the problem of spectral interference. This approach is based on calculating the first, second, or higher-order mathematical derivatives of the experimentally obtained raw absorbance spectrum. On the calculated derivative spectra, the objective is to identify specific wavelengths, termed 'zero-crossing points,' where the derivative signal of one component in the mixture is nullified (or approaches zero very closely), while other components exhibit a significant derivative signal. Suppose such suitable zero-crossing points exist for all components intended for analysis in the mixture. In that case, the concentration of each component in the mixture can be quantitatively determined without interference from the spectral contributions of other components using calibration equations established at these specific wavelengths. When the first-order derivative spectrum does not provide sufficient resolution, the analytical potential can be assessed by examining second or higher-order derivative spectra. Consequently, derivative spectrophotometry is an effective analytical method that enables the simultaneous and individual quantification of components in complex dyestuff mixtures, even utilizing conventional ultraviolet-visible (UV-Vis) spectrophotometers that are commonly available in laboratories and are relatively low-cost. A synthetic dye mixture of Acid Violet 90 (AV 90) and Reactive Yellow 145 (RY 145) was treated with non-viable Cladosporium cladosporioides biomass. Individual concentrations were calculated using a first-order derivative spectrophotometric method. Calibration curves were plotted at wavelengths of 578.4 nm for Acid Violet 90 and 318.2 nm for Reactive Yellow 145 in the derivative spectrum, respectively. The calculated limit of quantification (LOQ) values were approximately 2.5 mg/L for Acid Violet 90 and approximately 1.5 mg/L for Reactive Yellow 145. The mean percentage recovery values obtained were around 100%. The highest removal efficiency (100%) for both dyes was achieved at pH 4, using 0.25 g of biomass and an initial concentration of 50 mg/L for each dye, with a shaking speed of 150 rpm over a 60-minute reaction period. Hydrochloric acid solution was utilized for biomass regeneration, and in the third cycle, removal efficiencies remained at 99% for Acid Violet 90 and 89% for Reactive Yellow 145.