This paper discusses the color stripping of cotton fabric dyed with four reactive dyes using ozone. An ozone color stripping process has been optimized in terms of pH, ozone dose, treatment time and dye concentration. Color stripping efficiency of the process is evaluated in light of the color properties including Lightness (L*), Lightness Difference (∆L*), and Color Difference (∆E*) in addition to strength properties, i.e., copper number and degree of polymerization as well as compared with a control method (conventional reductive color stripping method). The results demonstrate maximum color stripping at an ozone dose of 10 g/h, exposure time of 45 min, and pH maintained at 5. The Stripping Efficiency, however, decreases with increasing dye concentration from 0.5% to 4%, which implies that decolorization of dyed fabric with higher initial dye concentration requires higher ozone dose and/or longer exposure time. The strength of the ozone-stripped fabric sample is almost similar to that of control. The chemical oxygen demand of effluent generated by ozone stripping process is 97% lower than the effluent produced by the conventional stripping method. The Ozone Stripping Process hence proves to be environment-friendly as it consumes less water, energy, and chemicals.

Levan is a homopolysaccharide of fructose units that repeat as its structural core. As an exopolysaccharide (EPS), it is produced by a great variety of microorganisms and a small number of plant species. The principal substrate used for levan production in industries, i.e., sucrose, is expensive and, hence, the manufacturing process requires an inexpensive substrate. As a result, the current research was designed to evaluate the potential of sucrose-rich fruit peels, i.e., mango peels, banana peels, apple peels, and sugarcane bagasse, to produce levan using Bacillus subtilis via submerged fermentation. After screening, the highest levan-producing substrate, mango peel, was used to optimize several process parameters (temperature, incubation time, pH, inoculum volume, and agitation speed) employing the central composite design (CCD) of response surface methodology (RSM), and their impact on levan production was assessed. After incubation for 64 h at 35 °C and pH 7.5, the addition of 2 mL of inoculum, and agitation at 180 rpm, the highest production of levan was 0.717 g/L of mango peel hydrolysate (obtained from 50 g of mango peels/liter of distilled water). The F-value of 50.53 and p-value 0.001 were calculated using the RSM statistical tool to verify that the planned model was highly significant. The selected model’s accuracy was proven by a high value (98.92%) of the coefficient of determination (R²). The results obtained from ANOVA made it clear that the influence of agitation speed alone on levan biosynthesis was statistically significant (p-value = 0.0001). The functional groups of levan produced were identified using FTIR (Fourier-transform ionization radiation). The sugars present in the levan were measured using HPLC and the levan was found to contain only fructose. The average molecular weight of the levan was 7.6 × 10⁶ KDa. The findings revealed that levan can be efficiently produced by submerged fermentation using inexpensive substrate, i.e., fruit peels. Furthermore, these optimized cultural conditions can be applied on a commercial scale for industrial production and commercialization of levan.

In this research, potential of reusing bleach water bath was examined with respect to its effect on whiteness of the cotton fabric exposed to 50 g/h of ozone on pilot scale for 45 min with 3 kg of fabric charged fresh at each trial, along with the evaluation of the economic viability of this technology in terms of profit per batch as well as profit per unit product (fabric) computed by Cost of Goods Sold statement. Results have shown that water can be reused with insignificant change in whiteness, revolving around 54% and 60%, and that it harnesses a 7 Rupees profit per unit fabric or 21 Rupees profit per cycle, which seems quite acceptable at existing bleached fabric sale price.

Sodium hydrosulfite is conventionally used for the color stripping of reactive dyes in the textile industry. However, research has been focused on eco-friendly processes to reduce wastewater generation in recent years. This study is aimed at estimating the color stripping efficacy of ozone according to reactive dyes’ chromophore groups. The dyed cotton-knitted fabric with three reactive dyes that have phthalocyanine (Reactive blue 21), diazo (Reactive black 5) and monoazo (Reactive yellow 84) chromophores was treated with ozone. The effect of the experimental parameters (pH, ozone dose and treatment time) was examined on the dyed fabric samples in terms of lightness and bursting strength properties. The results show that the decolorization efficiency of ozone varies with the type of chromophore group. The maximum color removal was achieved for the Reactive blue 21 dye of the phthalocyanine group at optimum process conditions (pH 3, Ozone dose 7 g/h, exposure time 40 min) followed by the reactive dyes that have dioazo and monoazo chromophore groups, respectively. The bursting strength of the fabric sample decolorized using ozone remained stable throughout the study. Moreover, the ozone-stripping effluent meets the environmental quality standards and can be reused up to at least four cycles without affecting the stripping efficiency. Hence, it can provide a sustainable alternative to reduce water consumption in the textile sector.

A study was conducted to evaluate the effect of Piper nigrum (black pepper) leaf extract on on the growth performance, proximate composition, hematological parameters, and immune response of Labeo rohita fingerlings with an average weight of 22.14 ± 0.98g. Aftrer acclimation for two weeks, fish (n=25) were randomly selected and placed in four glass aquaria (T0, T1, T2 and T3) at constant water temperature (30.0 ± 1.0 °C), pH (7.50 ± 0.5) and total hardness (200 ± 2.0 mgL,-1) for a period of 12 weeks, with three replicates each. Fish were fed with P. nigrum leaf extract supplemented feed @ 0.0%, 1.0%, 2.0% and 3.0% in T0, T1,T2 and T3, respectively. At the end of experiment, five fish were randomly selected from each aquaria for proximate composition, gut and skin microbial load, hematological parameters. Total proteins, albumins, and globulins were also recorded to evaluate immunological memory. The result revealed that fish in T2 showed better growth performance with an average weight gain of 56.11 ± 0.51 g. Thus, it had been concluded that Piper nigrum, a medicinal plant, can also be used to enhance the growth performance and immune response of Labeo rohita as attractive alternatives against antibiotics and vaccines and has shown no negative side effects on fish health as well as on its environment.