Fermentasi etanol menggunakan bakteri Zymonas mobilis dari glukosa hasil hidrolisa enzimatik bagas

2018 ◽  
Vol 6 (2) ◽  
pp. 609
Author(s):  
S Saraswati

The resources and reserves of oil which is a non renewable energy are very limited, while the oil consumption is increasing continuously. It is necessary to look for alternative energy. Etanol, a liquid energy, is a renewable alternative energy. Glucose can be used as raw material for etanol production. Glucose can be obtained by enzymatic hydrolysis of bagasse which is a solid waste of sugar canefactory. The objective of this research was to get the optimum condition of etanol production using bagasse as raw material. The experimental research consisted of 2 steps. First step : enzymatic hydrolysis of bagasse with chemical pretreatment process, and the second step was fermentation process using Zymomonas mobilis bacteria. Variables of thefirst step were the NaOH concentration (5%, 7% and 9%) as a pretreatment agent, and cellulase enzyme used (30, 40 and 50 cellulase enzyme  units/gram bagasse). For the second step, the variables were glucose concentration (I2.5%, 15%, 20%, 22.5%, and 25%) and the fermentation time (20, 24, 28, 32, 36, 40 and 48 hours). The experiment showed that the best result of the enzymatic hydrolysis could be obtained by NaOH 7% as chemical pretreatment agent and using 50 units of cellulase enzyme/gram bagasse. The cellulose conversion of bagasse was 87% within 42 hours period time. The highest etanol concentration of the fermentation process was 9.238% (weight %) and the yield was 0.4912 grams etanol/gram glucose. It was reached by using 22.5% glucose during 48 hours fermentation  time.Keywords: etanol; fermentation; Zymomonas mobilis; glucose; hydrolysis; cellulase enzyme; pretreatment;bagasse AbstrakCadangan minyak bumi yang merupakan non renewable energy (energi tak terbarukan) sangat terbatas, sedang konsumsinya terus meningkat.  Untuk itu perlu  dicari energi alternatif. Etanol merupakan salah satu energi cair alternatif yang terbarukan (renewable). Bahan baku etanol antara lain adalah glukosa. Glukosa dapat diperoleh dari hidrolisa enzimatik bagas yang merupakan limbah pabrik gula. Penelitian ini bertujuan  untuk  mendapatkan  kondisi yang  optimum  dari pembuatan  etanol  dengan  bahan baku bagas. Penelitian  experimental  meliputi  dua tahap.  Tahap I  : proses  hidrolisa  enzimatik  dari bagas dengan perlakuan pendahuluan  (pretreatment), dan tahap II adalah proses fermentasi  dengan bakteri Zymomonas  mobilis.  Variabel pada  tahap I  adalah  konsentrasi  NaOH  sebagai  pretreatment   agent sebesar 5%, 7% dan 9% serta pemakaian enzim selulase : 30, 40 dan 50 unit enzim selulase/gram bagas. Variabel untuk tahap II  adalah konsentrasi glukosa:  12.5%,  15%, 20%, 22.5%  dan 25% dan waktu fermentasi  20, 24, 28, 32, 36, 40  dan 48 jam.  Hasil penelitian  menunjukkan  bahwa  untuk  hidrolisa enzimatik hasil yang terbaik diperoleh dengan NaOH 7% dan 50 unit enzim selulase/gram bagas dengan konversi selulosa 87% dan waktu 42 jam. Untuk fermentasi kadar etanol tertinggi diperoleh pada konsentrasi glukosa 22.5% yaitu sebesar 9.238%, waktu 48 jam dan yield 0.4912 gram etanollgram glukosa.Kata Kunci: etanol; fennentasi; Zymomonas mobilis; glukosa; hidrolisa ; enzim selulase; pretreatment; bagas.

2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.


2014 ◽  
Vol 34 (1) ◽  
pp. 167-173 ◽  
Author(s):  
Aikaterini I. Vavouraki ◽  
Vassiliki Volioti ◽  
Michael E. Kornaros

2018 ◽  
Vol 33 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Dan Huo ◽  
Qiulin Yang ◽  
Guigan Fang ◽  
Qiujuan Liu ◽  
Chuanling Si ◽  
...  

Abstract Eucalyptus residues from pulp mill were pretreated with aqueous ammonia soaking (AAS) method to improve the efficiency of enzymatic hydrolysis. The optimized condition of AAS was obtained by response surface methodology. Meanwhile, hydrogen peroxide was introduced into the AAS system to modify the AAS pretreatment (AASP). The results showed that a fermentable sugar yield of 64.96 % was obtained when the eucalypt fibers were pretreated at the optimal conditions, with 80 % of ammonia (w/w) for 11 h and keeping the temperature at 90 °C. In further research it was found that the addition of H2O2 to the AAS could improve the pretreatment efficiency. The delignification rate and enzymatic digestibility were increased to 64.49 % and 73.85 %, respectively, with 5 % of hydrogen peroxide being used. FTIR analysis indicated that most syringyl and guaiacyl lignin and a trace amount of xylan were degraded and dissolved during the AAS and AASP pretreatments. The CrI of the raw material was increased after AAS and AASP pretreatments, which was attributed to the removal of amorphous portion. SEM images showed that microfibers were separated and explored from the initial fiber structure after AAS pretreatment, and the AASP method could improve the destructiveness of the fiber surface.


Holzforschung ◽  
2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Fokko Schütt ◽  
Jürgen Puls ◽  
Bodo Saake

Abstract Steam refining was investigated as a pretreatment for enzymatic hydrolysis of poplar wood from a short rotation plantation. The experiments were carried out without debarking to use an economically realistic raw material. Steam refining conditions were varied in the range of 3–30 min and 170–220°C, according to a factorial design created with the software JMP from SAS Institute Inc., Cary, NC, USA. Predicted steaming conditions for highest glucose and xylose yields after enzymatic hydrolysis were at 210°C and 15 min. Control tests under the optimized conditions verified the predicted results. Further pretreatments without bark showed that the enzymes were not significantly inhibited by the bark. The yield of glucose and xylose was 61.9% of theoretical for the experiments with the whole raw material, whereas the yield for the experiments without bark was 63.6%. Alkaline extraction of lignin from the fibers before enzymatic hydrolysis resulted in an increase of glucose yields from mild pretreated fibers and a decrease for severe pretreated fibers. The extracted lignin had a high content of xylose of up to 14% after very mild pretreatments. On the other hand, molecular weights of the extracted lignin increased substantially after pretreatments with a severity factor above 4. Hence, alkaline extraction of the lignin seems only attractive in a narrow range of steaming conditions.


2018 ◽  
Vol 154 ◽  
pp. 01004
Author(s):  
Sutarno ◽  
Abdul Malik Kholiq

A research on robusta coffee waste has been conducted as a renewable energy material - Bioethanol. This research was carried out by hydrolysis and fermentation process using Zymomonasmobilis and Saccharomyces cerevisiae (Zymomonasmobilis) bacteria to obtain the best catalyst type in the process of hydrolysis of coffee skin to glucose and the effect of fermentation time on bioethanol content produced. This research was conducted by varying the fermentation time of 7 days; 8 days; 9 days and 10 days. The fermentation fluid was then distilled and tested for bioethanol using a refractometer. Furthermore, bioethanol concentration in the analysis using.


2021 ◽  
Author(s):  
Youshan Sun ◽  
Xuyang Zhang ◽  
Fei Wang ◽  
Meiyan Wang

Abstract Calcium peroxide (CaO2) pretreatment was employed to remove lignin and subsequently facilitate enzymatic digestibility of wheat straw. An optimal condition was obtained at 130°C for 10 min with 0.35 g CaO2/g dried material of wheat straw and a 1:8 solid-liquid ratio. Under this condition, 57.8% of initial lignin, 7.2% of initial glucan, and 30.6% of initial xylan were removed from CaO2 pretreatment, respectively, meanwhile, a glucose recovery of 90.6 % and a xylose recovery of 65.9 % were obtained from the subsequent enzymatic hydrolysis of treated wheat straw, respectively. CaO2 pretreatment was proved to be a very effective method in delignification and improving enzymatic digestibility. Compared to raw material, the complex structure of lignocellulose was drastically disrupted with a wide emergence of scaly bulges and fully exposed microfibers, which still retained in the solid.


2020 ◽  
Author(s):  
Agha Amad Nabi ◽  
Muhammad Azhar Magsi ◽  
Suresh Ramakrishnan ◽  
Fayaz Hussain Tunio

Abstract The foremost need for countries especially Pakistan and other Asian countries is the hunt for renewable and alternative energy because the scarcity of energy is faced by many countries like Pakistan. There are a number of approaches seeking to demonstrate the diffusion of renewable energy technologies (RET). Learning and experience curves are the highest generally exercised instruments, followed by further economic, policy- and barrier-related analyses. The purpose of this study is to support research on the role of raw material prices specifically oil price and gas price on Renewable energy diffusion. Panel regression with fixed effects model is applied on data of 3 Asian countries namely Pakistan, India, and China for the period 1990 to 2012 gathered from World Bank and EIA (Energy Information Administration). The findings reveal that the model confirms an adequate fit and a very significant influence of oil prices on investments in renewable energy technology capacity whereas the insignificant influence of natural gas prices in a renewable energy technology capacity.


Author(s):  
Mykola Stadnik ◽  
Andrii Shtuts ◽  
Oleksandr Pylypenko

Ukraine has untapped potential for the production of own energy from renewable sources - processing of livestock waste (animal manure and bird droppings) with the formation of biogas, which can then be used to produce electricity, heat or fuel - analogues of natural gas (methane) (in particular, for own needs of farms). Currently in Ukraine, the generation of large amounts of waste on industrial farms is an environmental problem that needs to be addressed. Recycling livestock waste to generate biogas will partially solve environmental problems, as well as benefit from decentralized renewable energy production or fuel production. The role of renewable energy sources in energy production is constantly growing and now the issue of increasing the share of renewable sources in the energy balance of each country is relevant. In the supply of primary energy, the share of renewable energy accounts for 13% worldwide. Of these, biomass accounts for 10%, or 258 million tons per year, ie in the world biomass provides the largest share of energy supply from renewable sources. Domestic agricultural enterprises are significant consumers of fuel and energy resources, so they face the objective need to use alternative energy sources, including biofuels and the introduction of innovative energy-saving technologies. Biogas production is an efficient and attractive investment technology, due to the presence of significant raw material potential, favorable climatic and other. However, the level of introduction of this type of energy in the agro-industrial complex is insufficient, which is due to a number of issues, including insufficient level of practical recommendations for choosing power generators, their number, modes of operation taking into account daily energy consumption schedule, load and optimal efficiency. installations while providing autonomous power supply of the enterprise. This paper determines the level of energy supply of livestock farms through the use of biogas plants as a source of energy used for livestock waste.


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