Method for producing hydrogen by using waste bananas through photosynthetic organisms
阅读说明：本技术 一种利用废弃香蕉进行光合生物制氢的方法 (Method for producing hydrogen by using waste bananas through photosynthetic organisms ) 是由 路朝阳 张全国 孙勇 李文哲 张寰 曲斌 张宁远 刘玲慧 杨旭东 于 2021-07-19 设计创作，主要内容包括：本发明涉及一种利用废弃香蕉进行光合生物制氢的方法,具体为：取1-5 g废弃香蕉,加入80-120 mL柠檬酸-柠檬酸钠缓冲溶液,然后按照0.1-0.3 mL/g的剂量加入纤维素酶；用碱液中和至中性,然后加入对数期后期的光合细菌和产氢培养基,在温度28-32℃、光照强度2500-3500 Lux的条件下进行产氢。该方法以厨余垃圾废弃香蕉为原料生产清洁的氢气能源,变废为宝,成本低,且产氢效率高。(The invention relates to a method for producing hydrogen by utilizing waste bananas through photosynthetic organisms, which comprises the following specific steps: taking 1-5 g of waste bananas, adding 80-120 mL of citric acid-sodium citrate buffer solution, and then adding cellulase according to the dosage of 0.1-0.3 mL/g; neutralizing with alkali liquor to neutrality, adding photosynthetic bacteria and hydrogen production culture medium at late logarithmic phase, and producing hydrogen at 28-32 deg.C under illumination intensity of 2500-. The method uses the kitchen waste bananas as the raw material to produce clean hydrogen energy, changes waste into valuable, and has low cost and high hydrogen production efficiency.)
1. A method for producing hydrogen by using waste bananas through photosynthetic organisms is characterized in that 1-5 g of waste bananas are taken, 80-120 mL of citric acid-sodium citrate buffer solution is added, and cellulase is added according to the dosage of 0.1-0.3 mL/g; neutralizing with alkali liquor to neutrality, adding photosynthetic bacteria and hydrogen production culture medium at late logarithmic phase, and producing hydrogen at 28-32 deg.C under illumination intensity of 2500-.
2. A method for photosynthetic biological hydrogen production by using waste bananas as claimed in claim 1, wherein the waste bananas are obtained by the following pretreatment: cutting waste banana into 4-6 mm cubes, and baking at 70-80 deg.C for 48-72 hr.
3. A method for photosynthetic biological hydrogen production by using waste bananas as claimed in claim 1 or 2, wherein the concentration of the citric acid-sodium citrate buffer solution is 0.05 mol/L, and the pH is 4.8.
4. A method for photosynthetic hydrogen production by using waste bananas as claimed in claim 3, wherein the photosynthetic bacteria in the late logarithmic phase are obtained by: inoculating HAU-M1 photosynthetic hydrogen-producing bacteria into growth medium, and culturing in constant temperature incubator at 28-32 deg.C and illumination intensity of 2500-.
5. A method for photosynthetic hydrogen production by use of waste bananas as claimed in claim 4, wherein the growth medium consists of: 1 g/L yeast extract, 1 g/L NH4Cl，0.2 g/L K2HPO4，2 g/L NaHCO3，4 g/L CH3COONa, 2 g/L NaCl and 0.2 g/L MgSO4。
6. The method for photosynthetic biological hydrogen production by using waste bananas as claimed in claim 1, wherein the hydrogen production medium consists of: 0.1 g/L yeast extract, 3.56 g/L sodium glutamate, 0.4 g/L NH4Cl，0.5 g/L K2HPO4，0.2 g/L MgCl2And 2 g/L NaCl.
Technical Field
The invention belongs to the technical field of photosynthetic hydrogen production, and particularly relates to a method for producing hydrogen by using waste bananas through photosynthetic organisms.
Background
With the rapid rise of China, China has come to pay great attention to the influence of ecological environment safety on the life of people.
Based on a research in Shanghai City in China, the kitchen waste accounts for 51.8% of the total amount of the waste, so that the burden of subsequent waste treatment modes (landfill and incineration) is reduced, the carbon emission is reduced, and the energy can be further extracted from the kitchen waste. By 2025, 1.4X 108 tons of kitchen garbage in China can be obtained, which is equivalent to 1000 ten thousand tons of coal generated [8 ]. However, the current treatment capacity of China is only 0.098 x 108 tons, and the huge gap of kitchen waste treatment brings huge challenges to the social and environmental safety problems. According to Chinese dietary habits, the food waste roughly comprises grains (noodles and rice), vegetables (Chinese cabbage and potato), fruits (apple and banana) and meat (pork and chicken) according to the components. The kitchen garbage of fruits contains a large amount of sugar, and can be directly degraded and utilized in the resource utilization process. Habibi et al use apple waste to produce chitosan under the action of Aspergillus terreus and optimize the process conditions. Mago et al found that the addition of 20-40% banana waste can improve the performance of earthworm cow dung and promote the production and reproduction of earthworms. Mishra et al found that acid treatment of banana peel resulted in higher delignification rates and higher butanol titers (7.4 g/L) at lower reducing sugar loadings (20 g/L), but there is currently no report on the use of waste bananas for biological hydrogen production.
The method for producing hydrogen by using waste bananas through photosynthetic organisms can produce clean hydrogen energy, is simple to operate, low in cost and high in efficiency, and is a resource utilization mode worth popularizing.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method for producing hydrogen by using waste bananas through photosynthetic organisms. The method uses the kitchen waste bananas as the raw material to produce clean hydrogen energy, changes waste into valuable, and has low cost and high hydrogen production efficiency.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for producing hydrogen by using waste bananas through photosynthetic organisms comprises the following specific steps: taking 1-5 g of waste bananas, adding 80-120 mL of citric acid-sodium citrate buffer solution, and then adding cellulase according to the dosage of 0.1-0.3 mL/g; neutralizing with alkali liquor to neutrality, adding photosynthetic bacteria and hydrogen production culture medium at late logarithmic phase, and producing hydrogen at 28-32 deg.C under illumination intensity of 2500-.
Further, in order to increase the hydrogen production, the waste bananas are preferably obtained by the following pretreatment: cutting waste banana into 4-6 mm cubes, and baking at 70-80 deg.C for 48-72 hr to remove water.
Further, the concentration of the citric acid-sodium citrate buffer solution is 0.05 mol/L, and the pH value is 4.8.
Further, the photosynthetic bacteria in the late logarithmic phase are obtained by the following steps: inoculating HAU-M1 photosynthetic hydrogen-producing bacteria into growth medium, and culturing in constant temperature incubator at 28-32 deg.C and illumination intensity of 2500-.
Specifically, the growth medium preferably has a composition of: 1 g/L yeast extract, 1 g/L NH4Cl，0.2 g/L K2HPO4，2 g/L NaHCO3，4 g/L CH3COONa, 2 g/L NaCl and 0.2 g/L MgSO4。
Specifically, the hydrogen production medium preferably comprises the following components: 0.1 g/L yeast extract, 3.56 g/L sodium glutamate, 0.4 g/L NH4Cl，0.5 g/L K2HPO4，0.2 g/L MgCl2And 2 g/L NaCl.
Hydrogen as a new star rising in novel energy slowly becomes an extremely important part in the field of new energy, the hydrogen has the characteristics of cleanness and high efficiency as the energy and is one of the most promising research objects in the research field of new energy at present, and in agricultural production and population countries in China, a large amount of waste household garbage and agricultural production waste are generated every day, rotten fruits are rather numerous, and the rotten fruits can be used as raw materials for biological hydrogen production, so that how to recover the household garbage and the agricultural production waste can change waste into valuable. Meanwhile, the hydrogen production efficiency is improved, so that the hydrogen production efficiency is popularized to each city, which becomes an important subject. The invention researches the influence of the concentration of the waste banana substrate on the gas production rate, the hydrogen production rate, the gas production rate and the hydrogen production rate, thereby obtaining whether the hydrogen production technology of the rotten banana is feasible or not; simultaneously researches the pH value and OD of the fermentation liquid in each hydrogen production process when different substrate concentrations are adopted540The value, the oxidation-reduction potential, the change rule of the reducing sugar content and the like.
The method for producing clean hydrogen energy by using the waste bananas from kitchen wastes as the raw materials changes waste into valuable, and has low cost and high hydrogen production efficiency. Compared with the prior art, the method has the following beneficial effects: 1) the banana waste is degraded, so that the environmental pollution is avoided; 2) generating clean hydrogen energy; 3) resource waste is avoided.
Drawings
FIG. 1 is a graph showing the effect of different substrate concentration experimental groups on pH;
FIG. 2 is a graph showing the effect of experimental groups of different substrate concentrations on the change in the mass concentration of reducing sugars;
FIG. 3 is a graph showing the effect of reaction solutions of different substrate concentrations on the cumulative amount of hydrogen produced;
FIG. 4 is a graph showing the effect of reaction solutions of different substrate concentrations on hydrogen production rate;
FIG. 5 is a graph showing the effect of different substrate concentrations on redox potential;
FIG. 6 is a graph showing the effect of different substrate concentrations on hydrogen production;
FIG. 7 shows the effect of reaction solutions with different substrate concentrations on hydrogen concentration.
Detailed Description
The technical solution of the present invention is further described in detail below, but the scope of the present invention is not limited thereto.
Experimental Material
The raw material (hydrogen-producing substrate) selected in the experiment is waste banana in a kitchen, and is pretreated as follows: cutting waste banana into 5 mm cubes, and baking at 75 deg.C for 48 hr.
The bacteria and enzymes used in the experiment are photosynthetic bacteria and cellulase respectively. The photosynthetic bacteria are from a bacterial flora of HAU-M1 photosynthetic hydrogen-producing bacteria of Henan university of agriculture, the bacteria mainly comprise 5 photosynthetic bacteria such as rhodospirillum rubrum, rhodopseudomonas capsulatum, rhodopseudomonas palustris, rhodobacter sphaeroides and rhodobacter capsulatum, and the mass fractions of the bacteria are respectively 27%, 25%, 28%, 9% and 11% (see the physiological characteristics and hydrogen-producing characteristic analysis of the HAU-M1 photosynthetic hydrogen-producing bacteria in the literature, the solar energy report, volume 36, No. 2 of 2015, and p 289-294). Cellulase enzymes (51 FPU/mL, Novozymes Biotechnology Co., Ltd., Denmark.).
The growth medium consists of: 1 g/L yeast extract, 1 g/L NH4Cl，0.2 g/L K2HPO4，2 g/L NaHCO3，4 g/L CH3COONa, 2 g/L NaCl and 0.2 g/L MgSO4。
The hydrogen production culture medium preferably comprises the following components: 0.1 g/L yeast extract, 3.56 g/L sodium glutamate, 0.4 g/L NH4Cl，0.5 g/L K2HPO4，0.2 g/L MgCl2And 2 g/L NaCl.
Buffer solution: a citric acid-sodium citrate buffer solution with the pH value of 4.8 and the concentration of 0.05 mol/L.
DNS reagent: weighing 3-5 dinitrosalicylic acid 6.3 g in a 500 mL big beaker, dissolving with a small amount of distilled water, adding a 2 mol/L NaOH solution 262 mL, mixing, adding a hot water solution containing 185 g of potassium sodium tartrate and fixing the volume to 500 mL, weighing anhydrous sodium sulfate 5 g and crystalline phenol 5 g, adding the anhydrous sodium sulfate and the crystalline phenol, and fully stirring with a glass rod until the anhydrous sodium sulfate and the crystalline phenol are completely dissolved. After cooling, the mixture is moved into a 1000 mL volumetric flask, and after the volume is increased to 1000 mL, the mixture is poured into a brown flask and placed in a dark greenhouse for one week before being used.
Experimental apparatus and instrument
Experimental apparatus: a triangular flask with a rubber plug opening at the upper part with good sealing performance is selected as a reaction device for experiment, a sealed gas sampling bag (Dalian Haideji science and technology Co., Ltd.) is connected on the rubber plug and is used as a hydrogen collecting device of the experiment, and the experiment device is put into a digital display biochemical incubator (double city analytical instrument Co., Ltd., Jiangyan city) for experiment.
A biochemical incubator: TF-100 digital display biochemical incubator (Shuangcheng analytical instruments, Inc. of Jiangyan).
A spectrophotometer: model 721 visible spectrophotometer (produced by shanghai cyanine scientific and technology limited). The wavelength range and the reproducibility are 190 + 1020nm and < + > -0.02 nm, the accuracy is < + > -0.5 nm, and the accuracy is +/-0.005A.
Analytical balance: analytical balance type F sialolis. The scale division is 0.1 mg, the maximum weighing 200 g.
A high-speed centrifuge: TGL-16B high speed centrifuge (Shanghai' an Tint scientific Instrument plant). The input power is 250 VA. Maximum volume 18 mL. The maximum rotation speed is 16500 r/min.
A pH meter: model FE28 pH meter (mettler-toledo instruments ltd). The working environment temperature is 5-40 ℃.
Anti-dry heating electric cup: HX-350A type dry-burning-proof electric heating cup (Chao' an district color pond Zhen Haoxing hardware and electrical equipment factory, Chao Zhou city). The heating power is 350W.
Electric heating air blast drying oven: 101-2A remote electric heating air-blast drying oven (Beijing Zhongwei industry Co., Ltd.). The power is 2.4 KW.
A gas chromatography analyzer: GC-14B gas chromatograph. 5A molecular sieve is used as a filler of a chromatographic column, nitrogen is used as a carrier gas, the flow rate is 45 mL/min, and high-purity hydrogen with the purity of 99.999 percent is used as standard gas. Chromatographic conditions: the injection port temperature is 100 deg.C, the column temperature is 80 deg.C, the TCD detector is 150 deg.C, the injection amount is 500 μ L, and the retention time is 2 min.
Experimental procedures and methods
1.3.1 Experimental group configuration
Selecting five experimental devices, dividing the pretreated waste bananas (used as substrates) into five parts, wherein the weight parts are 1 g, 2 g, 3 g, 4 g and 5 g respectively, adding the waste bananas into triangular flasks of the experimental devices respectively, and sequentially marking the experimental devices as 1, 2, 3, 4 and 5. Then 100 mL of 0.05 mol/L citric acid-sodium citrate buffer solution with pH4.8 was added, and then a corresponding dose of cellulase (liquid) was added to each flask at a dose of 0.2 mL/g banana, respectively.
Neutralization titration process
And (3) performing neutralization titration by using 5 mol/L KOH solution and hydrochloric acid solution containing 36-38%. The pH of each sample was measured by stirring with a glass rod while dropping until the pH was 7.
Inoculating photosynthetic bacteria
The HAU-M1 photosynthetic hydrogen-producing bacteria are inoculated in a growth culture medium and placed in a constant temperature incubator with the temperature of 30 ℃ and the illumination intensity of 3000 Lux for culturing for 48h, and the photosynthetic bacteria in the later logarithmic phase are obtained.
50 mL of late logarithmic phase photosynthetic bacteria and 50 mL of hydrogen-producing medium were added to each neutral sample.
Initial experiment
The treated five groups of experimental devices are put into an incubator, the temperature in the incubator is adjusted to 30 ℃, the illumination intensity is set to 3000 Lux, and the experiment formally starts after the devices are put. The experimental data are measured every 12h as a period.
Determination and recording of Experimental data
1.4.1 determination of gas production and content
The ability of the photosynthetic anaerobic bacteria to produce hydrogen can be expressed in terms of hydrogen production and hydrogen production rate. During measurement, gas generated by each experimental device is firstly extracted by a needle tube and then labeled. The volume of gas produced by each experimental set-up was read and recorded. Finally, the amount of hydrogen contained in the gas produced by each set of experimental devices was determined by means of a 6820GC-14B gas chromatograph. The gas is extracted regularly every 12 hours for measurement, the peak value of each group is recorded after measurement, and then the hydrogen content is calculated by the following formula (1) (refer to the literature: Luchaoyang, Wangyi, Jingyan, etc.. the research on the hydrogen production optimization experiment of the photosynthetic organisms of the maize straws based on the BBD model [ J ]. 2014, (8): 1511-: s represents the peak area of the generated gas for each group.
Y=0.0012*S+0.9388 (1)
1.4.2 determination of pH
1 mL of liquid was withdrawn from the experimental set up using a small needle and placed in a plastic tube. The pH value tester is selected for measurement, the electrodes are cleaned by distilled water before measurement, and the electrodes are inserted into a plastic test tube after being wiped by paper. And reading and recording data after the tester reacts.
540Measurement of (2)
Taking a small amount of liquid by using a small needle tube, putting the liquid into a small plastic tube, putting the plastic tube into a centrifugal machine for centrifugation, extracting supernatant after the centrifugation is finished, adding 0.5 mL of DNS reagent after dilution, heating the mixture in a water bath at 100 ℃ for 5 min, cooling the mixture, and pouring the cooled mixture into a color developing vessel. Adjusting the wavelength of spectrophotometer to 540 nm, sequentially placing each group of liquid into spectrophotometer, and measuring corresponding OD540The value is obtained.
Determination of Hydrogen production Rate
The hydrogen production rate of each stage can be measured by dividing the hydrogen production by the time interval.
Determination of the Redox potential
1 mL of liquid was withdrawn from the experimental set up using a small needle and placed in a plastic tube. Cleaning the oxidation-reduction potential pen, wiping the oxidation-reduction potential pen dry, putting the oxidation-reduction potential pen into a solution to be tested, timing for 30 s and recording data after the oxidation-reduction potential table potential value data are stable.
Determination of specific Hydrogen production
The specific hydrogen production can be obtained by dividing the hydrogen amount by the total gas amount.
Measurement of cumulative Hydrogen production
The accumulated hydrogen production at each time can be obtained by adding the sum of the previous hydrogen production to the hydrogen production at each stage.
Results and analysis of the experiments
2.1 pH value variation in the Process of Hydrogen production by Experimental compositions of different substrate concentrations
During the experiment, the anaerobic bacteria produce a part of acidic substances through respiration, which is inevitable in the metabolic process and causes the reduction of pH value, and although the buffer effect of the buffer solution exists, the data analysis can clearly see that: the influence of the decreased pH value on the hydrogen production efficiency shows that the pH value does not generate hydrogen basically when reaching 5 according to the data, which shows that the proper pH value is beneficial to the hydrogen production rate and the hydrogen production efficiency.
The change conditions of the pH values of the experimental groups with different substrate concentrations in the experimental process are shown in figure 1, and according to experimental data, the pH values are in a whole descending trend along with the progress of the bacterial photosynthetic hydrogen production process, the pH values are all between 6.5 and 7 at the beginning of the experiment, and the pH values of the four groups are gradually reduced to between 5.5 and 6 along with the approach of the experiment. At the moment, the peak of hydrogen production is reached, and the pH value reaches a gradually stable state after rapidly decreasing from 12h to 24 h along with the respiration of the bacteria according to the graph. The hydrogen production peak is 24 h-48h, the pH value is slowly reduced, and the hydrogen production efficiency is highest. The pH of the first group was then even slightly raised, and after 48h the value began to fall rapidly, with only a small rise back up to 72 h, but at this point essentially no hydrogen was produced. And then descends again at 84 h. It can be seen that the change in pH has some periodicity. And does not fall straight. And the hydrogen production effect is best when the pH value is 5.5-6.
Quality concentration change of reducing sugar in hydrogen production process of experimental composition with different substrate concentrations
The mass concentration of reducing sugar in the experimental groups was varied for different substrate concentrations during the experiment as shown in FIG. 2. From experimental data it can be found: in the experimental process, the mass concentration of reducing sugar is in a descending trend, because bacteria need nutrition, small molecular monosaccharides in a substrate are continuously decomposed along with the respiration of reducing sugar consumption of the bacteria in the hydrogen production process, and the carbohydrate in the reaction liquid is continuously reduced. As can be seen from FIG. 2, the bacteria continuously breathe for 12 h-36h to consume the saccharides, and reach the peak of hydrogen production in 36h, at this stage, the bacteria activity is strongest, the life activity is most vigorous, and therefore the hydrogen production efficiency is also highest. Meanwhile, it can be seen that although the concentration of reducing sugar in experimental groups with different substrate concentrations has approximately the same change trend, the higher the substrate concentration is, the faster the reducing sugar consumption rate is, and the stronger the bacterial activity is. The mass concentration of reducing sugar is reduced within 36-48 h, the sugar substances are basically consumed, the concentration of reducing sugar in a part of experimental groups is basically unchanged after 48h, and hydrogen production is basically finished.
Effect of different substrate concentrations on cumulative Hydrogen production
The cumulative hydrogen production for the experimental groups at different substrate concentrations over the course of the experiment is shown in FIG. 3. The hydrogen amount is calculated from the experimentally measured hydrogen production amount, and the accumulated hydrogen amount can be obtained by adding the hydrogen produced in each time period to the previously produced hydrogen. From experimental data it can be found: hydrogen is not generated basically within 0 h-12 h, the life activity of the bacteria is not obvious at the moment, and the activity of the enzyme in the body is low. The consumption of sugars is also low. Hydrogen production started gradually from 12h to 24 h, but the rate of rise was slower. The accumulated hydrogen yield rises rapidly within 24-36 h, and at the moment, the hydrogen production rate is fastest, the bacterial activity is maximum, and the efficiency is highest. After 36h to 48h, the rise was slow, at which time the hydrogen generation rate was slowed. The substrate is gradually depleted. The cumulative hydrogen amount after 48h did not substantially change.
Effect of different substrate concentrations on Hydrogen production Rate
The hydrogen production rate variation of the experimental composition with different substrate concentrations during the experiment is shown in fig. 4. From experimental data it can be found: when the hydrogen production time is 12-24 h, the hydrogen production speed is slow, and the bacteria are not active enough. The substrate is used to perform the respiration of the bacteria. The hydrogen production rate obviously rises within 24-36 h, and the rising rate is fast and gradually reaches the peak value of the hydrogen production rate within 36 h. And (4) 36 h-48h, wherein the substrate is gradually consumed, the hydrogen production rate is gradually reduced, and the life activity of the bacteria is gradually limited. The hydrogen production rate slowly reached a trough over 48 h. After 48h, substantially no more hydrogen was produced and the substrate was substantially consumed.
Effect of different substrate concentrations on the Redox potential
The change in redox potential of the experimental group with different substrate concentrations during the course of the experiment is shown in FIG. 5. From experimental data it can be found: at 12h-24 h, the oxidation-reduction potential is basically negative and tends to rise, and the bacteria are not active enough. And when the time is 24-36 h, the gas production peak period is started, and the oxidation-reduction potential is rapidly reduced, which indicates that the bacteria start to carry out photosynthesis. The trend starts to rise again at 36 h-48h and is still negative, and hydrogen is still generated. The hydrogen production process is finished after the bacteria are killed by a large amount of bacteria and the hydrogen production process is finished at the moment.
Effect of different substrate concentrations on Hydrogen production
The experimental group specific hydrogen production changes for different substrate concentrations during the course of the experiment are shown in FIG. 6. From experimental data it can be found: the specific hydrogen production rate is increased slowly when the reaction time is 12-24 hours. And when the hydrogen production amount is increased to 36 hours, the peak is reached. The specific hydrogen production rate begins to decrease from 36h to 48 h. After 48h, substantially no hydrogen was produced, and only the first group of experimental groups peaked in specific hydrogen production at 72 h. The analysis reason is that the substrate concentration is too low, so that the bacteria are not enough to live, and the life activity of the bacteria is slow.
Effect of different substrate concentrations on Hydrogen concentration
The hydrogen concentration profile of the experimental group is shown in FIG. 7 for different substrate concentrations during the course of the experiment. From experimental data it can be found: the hydrogen concentration steadily rises between 12h and 36h, and the hydrogen concentration of three experimental groups reaches the peak value in 36h, the hydrogen concentration of the third experimental group continues to rise after 36h, the hydrogen concentration reaches the peak value in 48h, and the hydrogen concentration of the first experimental group reaches the peak value in 72 h. All experimental groups except the first group showed a substantial decrease in hydrogen concentration from 36h to 84h, and the hydrogen concentration dropped to zero after 48 h.
And (4) conclusion: the following conclusions can be drawn from the analysis of the experimental data: the substrate concentration has a remarkable effect on hydrogen production by photosynthetic organisms, and too high or too low a concentration can affect the activities of anaerobic bacteria and enzymes.
1) Different substrate concentrations have little effect on the trend of pH change, but the higher the substrate concentration, the faster the pH drop rate, since the vital activities of the cells produce acidic substances.
2) The difference of the substrate concentration basically has no influence on the change trend of the mass concentration of the reducing sugar, but the larger the substrate concentration is, the higher the starting point of the mass concentration of the reducing sugar is, and the reduction rate is also faster. This is because the substrate contains a large amount of organic polysaccharide molecules.
3) The influence of the substrate concentration on the accumulated hydrogen production is large, the hydrogen production amount is reduced when the substrate concentration is too low and the raw materials for natural bacterial photosynthesis are small, but the hydrogen production is not facilitated when the substrate concentration is too high, and the hydrogen production efficiency is higher when the substrate concentration is proper.
4) The influence of the substrate concentration on the hydrogen production rate is obvious, the hydrogen production process is very slow due to too low concentration, and the bacteria are not fully utilized due to too high concentration. The hydrogen production rate of the middle test group was the highest.
5) Different substrate concentrations also have certain influence on the hydrogen concentration, and the intermediate group with moderate concentration has the highest hydrogen concentration, so that the hydrogen production efficiency is not good when the concentration is too high or too low.
By combining the data analysis, the most suitable pH value for hydrogen production by the waste banana photosynthetic organisms is about 5.5, the most suitable substrate concentration is 15 g/L, the maximum accumulated hydrogen production amount reaches 118.52 mL, the peak value of the hydrogen production rate is reached in 36h in the hydrogen production process, and the basic hydrogen production is finished in 48 h.