A system for producing bioethanol from industrial tea waste

Abstract

A system for producing bioethanol from industrial tea waste, comprising: a substrate processing unit configured to process industrial tea waste by drying and pulverizing; a pretreatment unit configured for the physicochemical treatment of the processed tea waste by steam explosion and acid hydrolysis; a detoxification unit configured to detoxify and neutralize the pretreated tea waste; a fermentation unit configured to ferment the detoxified tea waste under controlled conditions with Saccharomyces cerevisiae; and an ethanol estimation unit configured to measure the ethanol concentration in the fermented product.

Description

FIELD OF THE INVENTION

[0001] The present disclosure relates to a system for producing bioethanol from industrial tea waste. More specifically, the present invention relates to a system for producing bioethanol from industrial tea waste of Camellia sinensis using Saccharomyces cerevisiae MTCC 3821. BACKGROUND OF THE INVENTION

[0002] The rapid growth of the world population and tea consumption results in enormous amounts of tea waste (approximately 5 million tons annually) from industrial processing and consumption. This waste, which consists primarily of unusable tea leaves, buds, and cut stems, poses significant environmental problems and complications for waste management.

[0003] At the same time, the global demand for renewable energy sources is increasing to reduce dependence on fossil fuels and lower CO2 emissions. Bioethanol, a promising alternative to conventional fuels, can be produced from lignocellulosic biomass such as tea waste, which is abundant, renewable, and cost-effective.

[0004] Tea waste is a second-generation raw material with a high holocellulose content and offers several advantages over first-generation raw materials such as sugarcane and corn, as it does not compete with food resources. However, the complex lignocellulosic structure of tea waste (consisting of lignin, cellulose, and hemicellulose) requires appropriate pretreatment to make the carbohydrates accessible for fermentation by microorganisms. This invention addresses both the problem of tea waste management and the need for sustainable biofuel production by converting industrial tea waste into bioethanol through an efficient pretreatment and fermentation system. Summary of the invention

[0005] The present disclosure relates to a system for producing bioethanol from industrial tea waste. The proposed system produces bioethanol from tea waste of Camelia sinensis using Saccharomyces cerevisiae MTCC 3821 as the fermentation strain. The results of bioethanol production showed that Saccharomyces cerevisiae MTCC 3821 produced bioethanol from industrial tea waste pretreated with 8% (w / v) HNO3 at an inoculum concentration of 2% in the presence of nutrient factor 3 at 32°C.

[0006] The present disclosure aims to provide a system for producing bioethanol from industrial tea waste. The system comprises: a substrate processing unit for processing industrial tea waste by drying and pulverization; a pretreatment unit for physicochemically treating the processed tea waste by steam explosion and acid hydrolysis; a detoxification unit for detoxifying and neutralizing the pretreated tea waste; a fermentation unit for controlled fermentation of the detoxified tea waste with Saccharomyces cerevisiae; and an ethanol measurement unit for measuring the ethanol concentration in the fermented product.

[0007] An object of the present disclosure is to provide a system for producing bioethanol from industrial tea waste.

[0008] Another object of the present disclosure is to develop an efficient system for converting industrial tea waste into bioethanol using Saccharomyces cerevisiae MTCC 3821 through controlled pretreatment and fermentation processes.

[0009] Another objective of the present disclosure is to establish an optimized circular approach for the sustainable reuse of waste from the tea industry while generating renewable energy.

[0010] To further clarify the advantages and features of the present disclosure, the invention will be explained in more detail with reference to specific embodiments illustrated in the accompanying drawings. These drawings illustrate only typical embodiments of the invention and are therefore not to be considered as limiting its scope. The invention will be described and explained in more detail with reference to the accompanying drawings. SHORT DESCRIPTION OF THE FIGURE

[0011] These and other features, aspects, and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters represent like parts throughout. Fig. 1 shows a block diagram of a system for producing bioethanol from industrial tea waste according to an embodiment of the present disclosure.

[0012] Those skilled in the art will also appreciate that the elements in the drawings are shown for convenience and are not necessarily to scale. For example, the flowcharts illustrate the method by key steps to enhance understanding of aspects of the present disclosure. Furthermore, with respect to device construction, one or more components of the device may be represented in the drawings by conventional symbols. The drawing may show only the specific details relevant to understanding embodiments of the present disclosure in order not to clutter the drawing with details that would be readily apparent to those skilled in the art from the present description. DETAILED DESCRIPTION:

[0013] To facilitate understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and a clear description will be given. However, the scope of the invention is not limited thereby. Changes and further modifications to the illustrated system, as well as further applications of the principles of the invention, are possible, as would normally occur to one skilled in the art to which the invention pertains.

[0014] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be limiting thereof.

[0015] References in this specification to "one aspect," "another aspect," or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, the language "in one embodiment," "in another embodiment," and similar language throughout this specification may or may not refer to the same embodiment.

[0016] The terms "comprises," "comprising," or other variations thereof are intended to cover non-exclusive inclusion, such that a process or method comprising a list of steps may include not only those steps, but also additional steps not expressly listed or inherent in that process or method. Likewise, the statement "comprises" for one or more devices, subsystems, elements, structures, or components does not exclude, without further limitation, the existence of other devices, subsystems, elements, structures, components, or additional devices, subsystems, elements, structures, or components.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. The systems, methods, and examples provided herein are for illustrative purposes only and should not be considered limiting.

[0018] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0019] Fig. 1 shows a block diagram of a system for producing bioethanol from industrial tea waste according to an embodiment of the present disclosure.

[0020] According to Fig.1, the system (100) comprises a substrate processing unit (102) configured for processing industrial tea waste by drying and pulverizing; a pretreatment unit (104) configured for the physico-chemical treatment of the processed tea waste by steam explosion and acid hydrolysis; a detoxification unit (106) configured for the detoxification and neutralization of the pretreated tea waste; a fermentation unit (108) configured for the fermentation of the detoxified tea waste under controlled conditions with Saccharomyces cerevisiae; and an ethanol estimation unit (110) configured for measuring the ethanol concentration in the fermented product.

[0021] In one embodiment, the substrate processing unit (102) comprises: a hot air oven configured to dry industrial tea waste at 60°C for 20 hours; and a hammer mill configured to pulverize the dried tea waste to pass through a 2.27 mm sieve.

[0022] In one embodiment, the pretreatment unit (104) comprises: an autoclave configured to perform a steam explosion at 15 psi pressure and 121°C temperature; a chemical treatment chamber configured to treat the tea waste with nitric acid; and a filtration system configured to separate the pretreated substrate.

[0023] In one embodiment, the detoxification unit (106) comprises: a superliming chamber configured to treat the hydrolysate with calcium oxide; a neutralization chamber configured to adjust the pH using hydrochloric acid; and an activated carbon treatment system configured to remove fermentation inhibitors.

[0024] In one embodiment, the fermentation unit (108) comprises: a temperature-controlled fermentation chamber (108a); a nutrient supply system (108b) configured to provide nitrogen, phosphorus, and growth factors; an inoculum preparation system (108c) configured to maintain Saccharomyces cerevisiae MTCC 3821; and a system for maintaining the anaerobic environment (108d).

[0025] In one embodiment, the nutrient delivery system (108b) is configured to supply: a nitrogen source selected from ammonium sulfate, sodium nitrate, or urea; a phosphorus source selected from potassium dihydrogen phosphate, dipotassium hydrogen phosphate, or sodium dihydrogen phosphate; and growth factors selected from combinations of yeast extract, malt extract, meat extract, peptone, soy peptone, or tryptone, and wherein the nutrient delivery system uses magnesium sulfate, 0.5 g / L; potassium chloride, 0.5 g / L, and ferrous sulfate, 0.01 g / L as general nutrients for all fermentation tests.

[0026] In one embodiment, the ethanol estimation unit (110) comprises: a spectrophotometer configured to measure absorbance at 584 nm; a chromic acid reagent preparation system; and a temperature-controlled water bath maintained at 60°C.

[0027] In one embodiment, the system (100) further comprises: a control unit (112) configured to maintain the fermentation temperature between 30°C and 34°C, monitor and control the inoculum concentration between 2% and 6%, and regulate the fermentation time up to 72 hours.

[0028] In one embodiment, the pretreatment unit (104) is further configured to maintain the nitric acid concentration between 2% and 10% v / v, control the duration of the steam explosion for 50 minutes, and maintain a substrate to liquid ratio of 1:10.

[0029] In one embodiment, the system (100) further comprises: a storage unit (114) configured to store processed tea waste at 4°C, store culture media at suitable temperatures, and store the fermentation products under controlled conditions.

[0030] The invention provides a comprehensive system for bioethanol production from industrial tea waste. The system comprises a series of integrated units for substrate preparation, pretreatment, detoxification, fermentation, and ethanol determination. Industrial tea waste is subjected to controlled drying and pulverization, followed by pretreatment by steam explosion and acid hydrolysis. The pretreated waste is detoxified and fermented under optimized conditions with Saccharomyces cerevisiae MTCC 3821. The system enables precise control of parameters such as temperature, inoculum concentration, and nutrient factors to maximize ethanol yield.

[0031] A substrate processing unit was configured to process Camellia sinensis industrial tea waste (ITW) collected from the tea industry in Jashpur (26°13'N 78°11'E / 26.22°N 78.18°E), Chhattisgarh, India. The collected ITW was dried in a convection oven at 60 °C for 20 hours and then pulverized in a hammer mill to pass it through a 2.27 mm sieve. The processed industrial tea waste was subsequently stored in airtight plastic bags at 4 °C to prevent possible spoilage or degradation. The wild-type strain used in this work was Saccharomyces cerevisiae MTCC 3821.

[0032] A pretreatment unit was configured to perform physicochemical treatment of the processed tea waste using steam explosion and acid hydrolysis. The pretreatment involved the use of nitric acid (HNO3) at varying concentrations of 2%, 4%, 6%, 8%, and 10% (v / v), in addition to a control test using only distilled water (DW) under identical conditions. One gram of the substrate was mixed with 10 ml of the respective acid solution or 10 ml of distilled water. The steam explosion was performed by placing the prepared mixtures in a 100 ml flask and subjecting them to rapid steam decompression in an autoclave at 15 psi and 121 °C for 50 minutes, with the steam release valve fully opened.Following the pretreatment process, the supernatant was filtered through wire mesh, collected in glass tubes, and stored at 4°C for subsequent biochemical analysis. After physicochemical treatment, the substrates were analyzed. The amount of reducing sugars (xylose and glucose) was determined using the dinitrosalicylic acid (DNSA) method. DNSA was freshly prepared by suspending 1 g of 3,5-dinitrosalicylic acid (DNSA), 200 mg of crystalline phenol, and 50 mg of sodium sulfite in 100 ml of 1% sodium hydroxide solution and stored at 4°C. To prepare a 40% Rochelle salt solution, 40 g of potassium sodium tartrate was suspended in 100 ml of DW. The absorbance relative to the optical density of the sample and standards was recorded using a UV-Vis double-beam spectrophotometer at 510 nm for glucose and 540 nm for xylose.

[0033] A detoxification unit is configured to detoxify and neutralize the pretreated tea waste, ensuring the removal of fermentation inhibitors commonly present in acidic hydrolysates. The detoxification process is carried out systematically using a superliming chamber, a neutralization chamber, and an activated carbon treatment system. The superliming chamber is designed to treat the hydrolysate with calcium oxide (CaO), thereby increasing the alkalinity of the solution and raising the pH to approximately 12-13. The hydrolysate then enters the neutralization chamber, where hydrochloric acid (HCl) is introduced to bring the pH to a neutral range. After neutralization, the mixture is gently mixed for approximately 30 minutes, followed by vacuum filtration to remove salts and precipitates.

[0034] The hydrolysate is then treated with activated carbon. 2.5% activated carbon is added to the mixture and shaken for 30 minutes in an orbital shaker to ensure complete absorption of the inhibitors. The reaction mixture is then filtered three times to effectively remove the activated carbon. The final pH is maintained between 6.0 and 6.5 to ensure optimal conditions for further processing.

[0035] The system is configured to maintain a yeast culture of Saccharomyces cerevisiae MTCC 3821 on malt yeast agar. The medium consisted of peptone, 5 g / L; malt extract, 3 g / L; glucose, 10 g / L; yeast extract, 3 g / L; and agar, 20 g / L, pH: 7.0 ± 0.3. Stock cultures of this organism were maintained at 4 °C. The nutrient medium for growing the yeast inoculum was yeast extract-potato dextrose medium, consisting of: yeast extract, 10 g / L; peptone, 20 g / L; and dextrose, 20 g / L, pH: 5.0 ± 0.2 for 72 h at 28 ± 0.5 °C. The culture (inoculum) was grown aerobically in 250-ml flasks containing the above-mentioned medium at 28 °C in a shaking incubator (Remi Scientific) at 250 rpm for 72 h. The active cells were centrifuged at 1300 rpm for 15 minutes, then rinsed with sterilized water and used as inoculum.

[0036] A fermentation unit ferments detoxified tea waste with Saccharomyces cerevisiae under controlled conditions. The fermentation unit includes a temperature-controlled fermentation chamber, a nutrient supply system for supplying nitrogen, phosphorus, and growth factors, an inoculum preparation system for maintaining Saccharomyces cerevisiae MTCC 3821, and a system for maintaining the anaerobic environment.

[0037] The fermentation process involves inoculating detoxified hydrolysates from 8% (v / v) HNO3-pretreated industrial tea waste (ITW) with Saccharomyces cerevisiae MTCC 3821 at varying inoculation concentrations of 2%, 4%, and 6%. Fermentation is carried out in a batch system using a 150-mL flask containing 100 mL of sterilized, detoxified hydrolysate with an initial substrate concentration of 10 g / L. The system is designed to operate under strictly anaerobic conditions for a period of 72 hours. Samples are then taken and centrifuged at 1300 rpm. The supernatants are subsequently analyzed to determine the ethanol concentration.

[0038] The nutrient supply system provides the nutrients required for the fermentation process, including nitrogen, phosphorus, and growth factors. Three nutrient factors (NF) were developed to investigate the effect of different nutrient sources on ethanol production. The nitrogen sources used include ammonium sulfate (0.3%), sodium nitrate (0.3%), and urea (0.3%). The phosphorus sources include potassium dihydrogen phosphate (0.15%), dipotassium hydrogen phosphate (0.15%), and sodium dihydrogen phosphate (0.15%). Growth factors in various formulations consist of yeast extract (0.5%), malt extract (0.5%), meat extract (0.5%), peptone (0.5%), soy peptone (0.5%), and tryptone (0.5%). In addition, the system uses magnesium sulfate (0.5 g / l), potassium chloride (0.5 g / l) and ferrous sulfate (0.01 g / l) as general nutrients in all fermentation tests.

[0039] The fermentation unit is also equipped with temperature control, allowing the investigation of ethanol production at three different incubation temperatures: 30 °C, 32 °C, and 34 °C. The influence of these operating parameters, including different inoculum concentrations, nutrient compositions, and temperature conditions, is systematically investigated to optimize ethanol yield. The integration of a controlled fermentation system ensures precise regulation of environmental conditions, thus enabling an efficient and reproducible ethanol production process from pretreated tea waste.

[0040] An ethanol determination unit is configured to measure the ethanol concentration in the fermented product using a systematic approach. The unit includes a spectrophotometer for measuring absorbance at 584 nm, a system for preparing chromic acid reagents, and a temperature-controlled water bath at 60°C. The total ethanol concentration in the fermentation medium is quantified using the chromic acid method, following the protocol for measuring absorbance at 584 nm using the spectrophotometer. The chromic acid reagent is prepared by suspending 34 grams of potassium dichromate in 500 milliliters of distilled water. 325 milliliters of concentrated sulfuric acid are added to this solution, and the final volume is adjusted to one liter. The ethanol concentration is estimated.For ethanol determination, test tubes containing one milliliter of different ethanol concentrations are used, and the total volume is adjusted to five milliliters using distilled water. A measured volume of five milliliters of chromic acid reagent is added to each test tube. The reaction mixture is incubated for 20 minutes in a temperature-controlled water bath at 60 °C. After incubation, the absorbance of each sample is measured at 584 nm using a UV-Vis double-beam spectrophotometer. The ethanol concentration in the fermented broth is then determined using a standard curve of absolute ethanol.

[0041] For statistical analysis, the experimental design follows the CCD technique (Central Composite Design). The total number of experimental combinations in the CCD is given by equation 2 K+ 2K + n0, where K is the number of independent variables and n0 is the number of replicates at the central point. Based on this equation, twenty experimental runs are required for the study. The dependent variable in the study is the ethanol concentration, denoted as Y (g / L). The independent variables include the incubation temperature (30°C, 32°C, and 34°C), represented as X1, the inoculum level or concentration (2%, 4%, and 6%), represented as X2, and nutrient factors (1, 2, and 3), represented as X3. A mathematical model is developed to establish the correlation between the dependent and independent variables. The second-order polynomial equation includes linear coefficients (i), quadratic coefficients (j), regression coefficients (b), the number of factors examined and optimized in the tests (k), and random errors (e). Y=bo+∑i=1kbixi+∑i=1kbijx2i+∑ii <jk∑i<jkbijxixj+e

[0042] The coefficient of determination (R 2) is used to evaluate the goodness-of-fit of the second-order equation, while the F-test is applied to determine its statistical significance. The significance of each coefficient, including the regression coefficients of the parameters, is analyzed using the Student's t-test. Probability values ​​(P-values) are used to evaluate the interaction effects between variables, thus indicating their interaction patterns. The optimization of the response surface equation to achieve maximum ethanol yield within the range of the process variables is performed using the Design Expert version 8.7.0.1 software. The software is also used for analysis of variance (ANOVA), which is applied to the final prediction equation.Based on the influence of three independent parameters—temperature, inoculum concentration, and nutrient factors—and their relationship to ethanol yield, while keeping other parameters constant, isoresponse contour plots are generated. These contour plots are analyzed to investigate the interaction between different parameters. The optimal concentration of each parameter is determined based on the elliptical configuration of the contour plots.

[0043] The experiment investigated ethanol production from industrial tea waste (ITW) of Camellia sinensis using Saccharomyces cerevisiae MTCC 3821. Pretreatment of the ITW with 8% HNO3 resulted in the highest total sugar concentration, making it the preferred hydrolysate for further detoxification, neutralization, and fermentation. The optimized parameters for ethanol production were an inoculum concentration of 2%, the presence of nutrient factor 3, and an incubation temperature of 32 °C, resulting in a maximum ethanol yield of 4.7 mg / ml.

[0044] A central composite design (CCD) was used to optimize the key fermentation parameters, and the response surface methodology (RSM) was employed to analyze their effects. The CCD matrix and ethanol concentration responses were plotted, and statistical analyses, including Student's t-test and Fisher's F-test, were performed. The regression model showed an F-value of 1.21, indicating the model's significance. The probability that this value was due to noise was only 38.09%. The lack of fit test yielded an F-value of 46.56, with a low probability (0.03%) of random error. This indicates that the model adequately describes the experimental results.

[0045] The regression analysis resulted in an R 2 -value of 0.5222. This indicates that the model accounted for about 52.22% of the response variation. The adjusted R 2-value of 0.0922 indicated a moderate model fit, since statistical models are generally considered reliable if their R 2 -value is close to 1. The predicted R 2 -value (0.3537) was consistent with the adjusted R 2 -value (0.4487) adequately, with a difference of less than 0.2. A "Fair Precision" of 4.601 further confirmed the model's ability to effectively navigate the design space.

[0046] The optimal conditions for ethanol production, as derived from the model, were an incubation temperature of 30 °C, an inoculum concentration of 4%, and a nutrient factor of 1. Under these conditions, the maximum ethanol yield was 2.42871 mg / ml. Response contour plots were used to visualize the interactions of the fermentation variables. These plots showed the influence of inoculum concentration, incubation temperature, and nutrient factors on ethanol production, with various variables kept constant at their central values.

[0047] Ethanol production from ITW is based on the hydrolysis of cellulose and hemicellulose to fermentable monomers such as xylose and glucose. Ultrasound-enhanced acid hydrolysis has been shown to improve sugar release, which is crucial for fermentation. Previous research has shown that Saccharomyces cerevisiae can efficiently convert tea waste hydrolysate into ethanol under optimized conditions. Studies have also investigated alternative strategies, such as the use of seawater-based systems to reduce freshwater consumption during fermentation.

[0048] In this study, S. cerevisiae achieved the highest ethanol yield at 30 °C with an inoculum concentration of 4% and nutrient factor 3. The nutrient factor components included ammonium sulfate (0.3%), potassium dihydrogen phosphate (0.15%), yeast extract (0.5%), and peptone (0.5%), which are known to promote yeast growth. Ethanol production ranged between 2.28 and 2.42 mg / ml under the tested conditions. This suggests that S. cerevisiae is a potent ethanol producer from ITW and is comparable to other strains tested in previous studies.

[0049] The results highlight the potential of industrial tea waste as a cost-effective feedstock for bioethanol production and offer the opportunity to add value to this agricultural byproduct. Given the high global demand for tea and the significant waste generation, the use of tea waste for bioethanol production represents an environmentally sustainable alternative to landfilling. Future research should focus on refining commercial production methods and exploring additional factors that could increase ethanol yield. The study underscores the importance of bioethanol production from tea waste as a promising approach for waste management and biofuel production, contributing to a more sustainable bio-based economy.

[0050] The drawings and the foregoing description illustrate examples of embodiments. Those skilled in the art will recognize that one or more of the described elements may well be combined to form a single functional element. Alternatively, certain elements may be separated into multiple functional elements. Elements of one embodiment may be added to another embodiment. For example, the order of the processes described herein may be changed and is not limited to the manner described herein. Furthermore, the actions of a flowchart need not be performed in the order shown; nor do all actions need to be performed. Also, actions that are not dependent on other actions may be performed in parallel with the other actions. The scope of the embodiments is in no way limited by these specific examples.Numerous variations, whether explicitly stated in the specification or not, such as differences in structure, dimensions, and use of materials, are possible. The scope of the embodiments is at least as broad as indicated in the following claims.

[0051] Advantages, further benefits, and solutions to problems have been described above with reference to specific embodiments. However, the advantages, advantages, solutions to problems, and any components that may result in or enhance an advantage, advantage, or solution are not to be construed as critical, required, or essential features or components of any or all of the claims. REFERENCES 100 The system comprises a substrate processing unit. 102 Substrate processing unit 104 Pretreatment unit 106 Detoxification Unit 108 fermentation unit 108a Temperature-controlled fermentation chamber 108b Nutrient supply system 108c Inoculum Preparation System 108d System for Maintaining the Anaerobic Environment 110 Ethanol estimation unit 112 Control unit 114 storage unit

Claims

[1] A system for producing bioethanol from industrial tea waste, comprising: a substrate processing unit configured to process industrial tea waste by drying and pulverizing; a pretreatment unit configured for the physicochemical treatment of the processed tea waste by steam explosion and acid hydrolysis; a detoxification unit configured to detoxify and neutralize the pretreated tea waste; a fermentation unit configured to ferment the detoxified tea waste under controlled conditions with Saccharomyces cerevisiae; and an ethanol estimation unit configured to measure the ethanol concentration in the fermented product. [2] The system of claim 1, wherein the substrate processing unit comprises: a convection oven configured to dry industrial tea waste at 60°C for 20 hours; and a hammer mill configured to pulverize the dried tea waste to pass through a 2.27 mm sieve. [3] The system of claim 1, wherein the pretreatment unit comprises: an autoclave that performs a steam explosion at 15 psi pressure and 121°C temperature; a chemical treatment chamber that treats the tea waste with nitric acid; and a filtration system that separates the pretreated substrate. [4] The system of claim 1, wherein the detoxification unit comprises: a superliming chamber configured to treat the hydrolysate with calcium oxide; a neutralization chamber configured to adjust the pH using hydrochloric acid; and an activated carbon treatment system configured to remove fermentation inhibitors. [5] The system of claim 1, wherein the fermentation unit comprises: a temperature-controlled fermentation chamber; a nutrient supply system for supplying nitrogen, phosphorus, and growth factors; an inoculum preparation system for maintaining Saccharomyces cerevisiae MTCC 3821; and a system for maintaining the anaerobic environment. [6] The system of claim 5, wherein the nutrient delivery system is configured to supply: a nitrogen source selected from ammonium sulfate, sodium nitrate, or urea; a phosphorus source selected from potassium dihydrogen phosphate, dipotassium hydrogen phosphate, or sodium dihydrogen phosphate; and growth factors selected from combinations of yeast extract, malt extract, meat extract, peptone, soy peptone, or tryptone, and wherein the nutrient delivery system uses magnesium sulfate (0.5 g / L); potassium chloride (0.5 g / L), and ferrous sulfate (0.01 g / L) as general nutrients for all fermentation tests. [7] The system of claim 1, wherein the ethanol estimation unit comprises: a spectrophotometer configured to measure absorbance at 584 nm; a chromic acid reagent preparation system; and a temperature-controlled water bath maintained at 60°C. [8] The system of claim 1, further comprising: a control unit configured to maintain the fermentation temperature between 30°C and 34°C, monitor and control the inoculum concentration between 2% and 6%, and regulate the fermentation time up to 72 hours. [9] The system of claim 1, wherein the pretreatment unit is further configured to maintain the nitric acid concentration between 2% and 10% v / v, control the duration of the steam explosion for 50 minutes, and maintain a substrate to liquid ratio of 1:

10. [10] The system of claim 1, further comprising: a storage unit configured to store processed tea waste at 4°C, store culture media at suitable temperatures, and store the fermentation products under controlled conditions.

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