Enhanced bio-hydrogen production from corn stalk by anaerobic fermentation using response surface methodology

Herein, the production of biohydrogen by dark fermentation was optimized using a novel hybrid approach that combines ANNs (artificial neural networks) with RSM (response surface methodology). Using the limited numbers of data (15 runs) as training data set together with one cross‐out method for validation, the complete 29 runs of well‐established data matrix were created from ANNs for RSM statistical analysis in order to correlated the critical process parameters with hydrogen production performance. This methodology was found to be robust, cost‐effective, reliable, and can be extensively analyzed the critical operational parameters, that is, carbon sources (obtained from potato peel wastes and starchy wastes), metal cofactor Fe0, pH, and dose levels of microbes on the hydrogen production, along with concentrations of other metabolites, such as acetic acid, propionic acid, butyric acid, valeric acid, and ethanol. The established ANNs‐RSM model using Box–Behnken design indicates the significant changes caused by the variations of a few critical operation parameters. The resultant model shows an exceptionally good result in terms of nonlinear noisy processes. Both single and multiple objective optimizations for dark hydrogen fermentation can achieve by using the established hybrid ANN‐RSM system. The optimal operating conditions (starch 6.2 kg/m3, pH 6.7, Fe0 11.7 g/m3, sludge 24.6 g/m3) could lead to the generation of hydrogen with a yield of 106.2 (cm3/g) and metabolites, that is, propionic acid (2.8 kg/m3), butyric acid (2E−2 kg/m3), valeric acid (4E−4 kg/m3) acetic acid (1.9 kg/m3), and ethanol (0.1 kg/m3) simultaneously.

Application of nanomaterials in dark or light-assisted fermentation for enhanced biohydrogen production: A mini-review

The excessive use of fossil fuels as the primary energy source has resulted in significant environmental and economic challenges, including greenhouse gas emissions and the depletion of finite fossil fuel resources. To address these issues, there is a growing need for alternative and sustainable energy sources. Hydrogen holds promise as a clean and renewable energy option, and biohydrogen, produced through biological water splitting using microorganisms, emerges as a potential solution. Shifting towards biohydrogen production can help reduce greenhouse gas emissions, promote energy security, and lessen dependence on finite fossil fuels, making it a crucial step towards a more sustainable energy future. The assessment of biohydrogen production was performed in the study using obligative facultative anaerobe Clostridium butyricum (NCTC 7423) in the batch experiments. The initial experiment tested the potential of the strain to produce hydrogen from pure carbohydrate sources glucose and starch. Under the inoculum to substrate ratio of 9%, the strain showed the yield of 1.23 mol H2 / mol glucose and 0.73 mol H2 / mol glucose from glucose and starch with the substrate degradation efficiency of 70% and 60% in glucose and starch. The theoretical yield of hydrogen from carbohydrate is 2 moles for butyrate pathway and 4 moles for acetate pathway and their respective efficiencies are 16.75% and 33.51%. The efficiency of the strain from the conducted experiments using glucose and starch were 60% and 36%. The effect of temperature was further tested for the provided strain which resulted in the improved substrate degradation efficiency from 70% to 90% but the hydrogen production reduced at higher temperature. The strain has been reported to utilise starch as a substrate, this study further tested the use of natural waste rich in carbohydrate which in this case was potato waste. The potato waste was able to produce hydrogen with accompanied pre-treatment method which helps to improve the hydrolysis of carbohydrate present in the biomass. The potato was thermally and mechanically treated for biohydrogen production, three types of potato wastes were tested and the higher biohydrogen production was achieved in the boiled potato waste compared to raw and dried potato waste. The yield of the raw, dry and boiled potato waste achieved in the study are 65.05 ml/ g VS, 30.58 ml/ g VS, 103.39 ml/ g VS. The possibility of hydrogen production from all types of waste showed that potato in any form can be used to produce biohydrogen. The biohydrogen energy obtained by treating three types of potato waste are 9.3 kJ, 3.5 kJ, and 12.9 kJ from raw, dry and boil potato. The COD reduction obtained in the three types of waste were 17%, 11% and 23 %. The possibility of biohydrogen production from potato is a step towards making this process viable and energy efficient. Biohydrogen production is affected by the process parameters, therefore response surface analysis was used to optimise the process parameter pH and temperature for biohydrogen production. The analysis showed that pH and temperature are significant factors for biohydrogen production and the optimum pH and temperature was found to be 4.5 and 39oC which resulted in 129.50 ml H2/g VS . The analysis of volatile fatty acid in the experiments also showed that the strain utilised butyrate pathway for biohydrogen production as the butyric acid production was dominant in all the experiments. By maintaining the pH and temperature the COD reduction further increase to 29% which shows that both pre-treatment and maintained process parameter can helps to improve the hydrogen yield. Biohydrogen offers a promising alternative to fossil fuels, and Clostridium butyricum shows potential for hydrogen production from various carbohydrate sources, including potato waste. By optimizing process parameters, such as pH and temperature, biohydrogen production efficiency can be significantly improved. The findings highlight the versatility and renewable potential of potato waste for biohydrogen production, contributing to the development of sustainable energy solutions and addressing environmental concerns associated with traditional fossil fuel usage. Further research and investment in biohydrogen technology are essential for achieving a sustainable energy future. Low production of biohydrogen compared to the quantity of hydrogen produced by conventional is a main challenge which can be resolved by simultaneously replicating the process on pilot-scale. Biohydrogen is a novel research area, it was intriguing working with the waste and the possibility of biohydrogen production gives the insight for the future how food industries can innovate and work on the infrastructure to utilise the waste generated on the site to add value to the waste. The statistical tool response surface methodology used for process optimisation was helpful and eliminated the hassle and huge number of experiments.

Abstract: This research optimizes dietary fiber extraction from corn stalks and addresses its potential use in processed meat and fish products. The research aims to optimize dietary fiber extraction from corn stalk and characterize its potential as a food ingredient. Corn stalks were extracted using NaOH for dietary fiber, the procedure involved cleaning, drying, extraction, bleaching, and drying. RSM optimization using Design-Expert software determined optimal NaOH concentration and extraction time for dietary fiber yield. Products were characterized by FTIR, SEM, and BET, as well as determining WHC and OHC. This study optimized the extraction of dietary fiber from corn stalk using NaOH. RSM identified optimal conditions, i.e., NaOH concentration (A) = 25.96% and extraction time (B) = 65.39 min, yielding 34.47% dietary fiber. Validation trials resulted in a 34.38 ± 0.04% yield. Product characterization (FT-IR, SEM, BET), as well as assessments of WHC and OHC demonstrate the potential of corn stalk as a dietary fiber source and its use as a filler for processed meat and fish products. Optimization of dietary fiber extraction from corn stalks, achieved a yield of 34.47%. The findings highlight the feasibility of corn stalks as a source of dietary fiber in processed foods and the use of NaOH in extraction for large-scale production. Keywords: chemical extraction, corn stalks, dietary fiber, Response Surface Methodology, sodium hydroxide

Effect of microwave irradiation pretreatment of cow dung compost on bio-hydrogen process from corn stalk by dark fermentation

The present work is a study of the performance and effect of operational parameters on biohydrogen production from palm oil mill effluent by dark fermentation in batch mode. The process parameters examined are pH (5, 5.5, and 6), temperature (30, 35, and 40 °C), substrate concentration (5000, 12 500, and 20 000 mg L−1) and inoculum volume (20, 25, and 30 mL). The inoculum concentration prepared was 10 000 mg L−1 volatile suspended solids. The experiments were designed by response surface methodology (RSM). The highest chemical oxygen demand (COD) removal, hydrogen percentage (H2%) and hydrogen yield (HY) obtained were 58.3%, 80%, and 4.83 mol H2/mole of COD consumed, respectively. Based on the experimental data obtained with the RSM design, gene expression programming (GEP) was developed to predict the COD removal, hydrogen production, and hydrogen yield as process responses. The projected models were assessed based on the correlation coefficient (R2), root mean square error, mean absolute relative error, scatter index, and BIAS. The results demonstrate that the GEP model outperformed the RSM model and was superior in predicting the response variables. Partial derivative sensitivity analysis was also employed to assess the effect of each variable on COD%, H2%, and HY prediction. The prediction uncertainty for COD%, H2%, and HY was quantified, and the results were ±0.11, ±0.17, and 0.015, respectively. According to the results, the GEP model is more efficient than the RSM model in predicting the experimental data for biological hydrogen production in the dark fermentation process.

Screening of biohydrogen production based on dark fermentation in the presence of nano-sized Fe2O3 doped metal oxide additives

An integrated method to produce fermented liquid feed and biologically modified biochar as cadmium adsorbents using corn stalks

Improvement of biohydrogen production by optimization of pretreatment method and substrate to inoculum ratio from microalgal biomass and digested sludge

With an overall aim of utilizing lignocellulosic food waste as feedstock for anaerobic fermentation and optimizing the reaction for improving energy output, a two-stage anaerobic dark fermentation reactor was set up. This study discusses the evaluation of different pre-treatment methods used to pre-treat the food waste before using it as a substrate for anaerobic fermentation. Five different techniques from physical, chemical, and biological pre-treatment methods, namely, autoclaving, acid pre-treatment, alkali pre-treatment, aeration, and fungal pre-treatment were used for pre-treatment of the substrate. The analysis was also evaluated by the multilevel categoric factorial design of the experiment model. The experiment found that all five pre-treatments improved the hydrogen and methane yield from the reaction. More precisely, fungal pre-treatment shows an almost 3.8-fold improvement in hydrogen yield compared to control conditions and a 1.7-fold increase in methane yield compared to control. The statistical analysis showed that the reaction time duration (day) has a more significant impact on the results than the pre-treatment technique. The model’s F-Values of 24.14 for hydrogen yield and 44.34 for methane yield indicate substantially. However, the actual hydrogen and methane yields are in good accord with the DOE predicted results.

Dark fermentative biohydrogen production using pretreated Scenedesmus obliquus biomass under an integrated paradigm of biorefinery

Boosting biohydrogen production from pretreated sugarcane bagasse dust via coupled dark fermentation and microbial electrolysis cell.

Sulfate- and pH-driven metabolic flexibility in sugarcane vinasse dark fermentation stimulates biohydrogen evolution, sulfidogenesis or homoacetogenesis

Lactate wastewater dark fermentation: The effect of temperature and initial pH on biohydrogen production and microbial community

Effect of an ozone pre-treatment on dark fermentation: Influence on the microbiota and pathogen removal.