Skip to main content
SpringerLink
Log in

A Feasible Approach for Bioethanol Production Using Conventional and New Feedstocks

  • Chapter
  • First Online:
Bioethanol Production

Part of the book series: Green Chemistry and Sustainable Technology ((GCST))

  • 562 Accesses

Abstract

Current energy demand, rising oil prices, and the consequences of using fossil fuels have increased the desire for alternate energy sources. Bioethanol obtained from new feedstocks has gained attention and led to the production of advanced bioethanol over conventional. In terms of sustainability, the production of so-called advanced bioethanol has various advantages over typical bioethanol production procedures. This could involve the utilization of non-food crops or residual biomass as a raw material, as well as a greater ability to reduce greenhouse gas emissions. The current chapter focuses on recent advances in the production of advanced bioethanol, highlighting current results from novel feedstock sources such as the municipal solid waste and certain industrial waste (e.g., residues from the paper industry, food, and beverage industries) and lignocellulosic feedstocks.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 139.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 179.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 179.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  1. Owusu, P. A., & Asumadu-Sarkodie, S. (2016). A review of renewable energy sources, sustainability issues and climate change mitigation. Cogent Engineering, 3(1), 1167990.

    Article  Google Scholar 

  2. Park, J. Y., Shiroma, R., Al-Haq, M. I., Zhang, Y., Ike, M., Arai-Sanoh, Y., Ida, A., Kondo, M., & Tokuyasu, K. (2010). A novel lime pretreatment for subsequent bioethanol production from rice straw–calcium capturing by carbonation (CaCCO) process. Bioresource Technology, 101(17), 6805–6811.

    Article  CAS  PubMed  Google Scholar 

  3. Jeevan Kumar, S. P., Sampath Kumar, N. S., & Chintagunta, A. D. (2020). Bioethanol production from cereal crops and lignocelluloses rich agro-residues: Prospects and challenges. SN Applied Sciences, 2(10), 1–11.

    Article  CAS  Google Scholar 

  4. Kalair, A., Abas, N., Saleem, M. S., Kalair, A. R., & Khan, N. (2021). Role of energy storage systems in energy transition from fossil fuels to renewables. Energy Storage, 3(1), e135.

    Article  Google Scholar 

  5. Chandel, A. K., Garlapati, V. K., Jeevan Kumar, S. P., Hans, M., Singh, A. K., & Kumar, S. (2020). The role of renewable chemicals and biofuels in building a bioeconomy. Biofuels, Bioproducts and Biorefining, 14(4), 830–844. Sage, R. F. (1999). Why C4 photosynthesis. C4 plant biology, 3–16.

    Google Scholar 

  6. Banerjee, R., Chintagunta, A. D., & Ray, S. (2019). Laccase mediated delignification of pineapple leaf waste: An ecofriendly sustainable attempt towards valorization. BMC Chemistry, 13(1), 1–11.

    Article  CAS  Google Scholar 

  7. Bušić, A., Marđetko, N., Kundas, S., Morzak, G., Belskaya, H., Ivančić Šantek, M., Komes, D., Novak, S., & Šantek, B. (2018). Bioethanol production from renewable raw materials and its separation and purification: A review. Food Technology and Biotechnology, 56(3), 289–311.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  8. Aarti, C., Khusro, A., & Agastian, P. (2018). Carboxymethyl cellulase production optimization from Glutamicibacter arilaitensis strain ALA4 and its application in lignocellulosic waste biomass saccharification. Preparative Biochemistry and Biotechnology, 48(9), 853–866.

    Article  CAS  PubMed  Google Scholar 

  9. Anwar, Z., Gulfraz, M., & Irshad, M. (2014). Agro-industrial lignocellulosic biomass a key to unlock the future bio-energy: A brief review. Journal of Radiation Research and Applied Sciences, 7(2), 163–173.

    Article  CAS  Google Scholar 

  10. Ballerini, D., Desmarquest, J. P., Pourquie, J., Nativel, F., & Rebeller, M. (1994). Ethanol production from lignocellulosics: Large scale experimentation and economics. Bioresource Technology, 50(1), 17–23.

    Article  CAS  Google Scholar 

  11. Saini, J. K., Saini, R., & Tewari, L. (2015). Lignocellulosic agriculture wastes as biomass feedstocks for second-generation bioethanol production: Concepts and recent developments. 3 Biotech, 5(4), 337–353.

    Google Scholar 

  12. Prasad, S., Singh, A., & Joshi, H. C. (2007). Ethanol as an alternative fuel from agricultural, industrial and urban residues. Resources, Conservation and Recycling, 50(1), 1–39.

    Article  Google Scholar 

  13. Munasinghe, P. C., & Khanal, S. K. (2010). Biomass-derived syngas fermentation into biofuels: Opportunities and challenges. Bioresource Technology, 101(13), 5013–5022.

    Article  CAS  PubMed  Google Scholar 

  14. Demirbas, A. (2007). Progress and recent trends in biofuels. Progress in Energy and Combustion Science, 33(1), 1–18.

    Article  CAS  Google Scholar 

  15. Wang, H., Wang, J., Fang, Z., Wang, X., & Bu, H. (2010). Enhanced bio-hydrogen production by anaerobic fermentation of apple pomace with enzyme hydrolysis. International Journal of Hydrogen Energy, 35(15), 8303–8309.

    Article  CAS  Google Scholar 

  16. Marzialetti, T., Valenzuela Olarte, M. B., Sievers, C., Hoskins, T. J., Agrawal, P. K., & Jones, C. W. (2008). Dilute acid hydrolysis of Loblolly pine: A comprehensive approach. Industrial & Engineering Chemistry Research, 47(19), 7131–7140.

    Article  CAS  Google Scholar 

  17. Dubois, J. L. (2011). Requirements for the development of a bioeconomy for chemicals. Current Opinion in Environmental Sustainability, 3(1–2), 11–14.

    Article  Google Scholar 

  18. Brussels, Belgium 2019. Biomass for Energy—Agricultural Residues and Energy Crops; BioEnergy_Europe: Factsheet

    Google Scholar 

  19. IEA. (2010) Sustainable Production of Second-Generation Biofuels; IEA: Paris, France.

    Google Scholar 

  20. Smullen, E., Finnan, J., Dowling, D., & Mulcahy, P. (2017). Bioconversion of switchgrass: Identification of a leading pretreatment option based on yield, cost and environmental impact. Renewable Energy, 111, 638–645.

    Article  CAS  Google Scholar 

  21. Hoadley, R. B. (2000). Understanding wood: a craftsman's guide to wood technology. Taunton press.

    Google Scholar 

  22. Neiva, D. M., Araujo, S., Gominho, J., de Cássia Carneiro, A., & Pereira, H. (2018). Potential of Eucalyptus globulus industrial bark as a biorefinery feedstock: Chemical and fuel characterization. Industrial Crops and Products, 123, 262–270.

    Article  CAS  Google Scholar 

  23. Romaní, A., Larramendi, A., Yáñez, R., Cancela, Á., Sánchez, Á., Teixeira, J. A., & Domingues, L. (2019). Valorization of Eucalyptus nitens bark by organosolv pretreatment for the production of advanced biofuels. Industrial Crops and Products, 132, 327–335.

    Article  CAS  Google Scholar 

  24. Zhao, J., Tian, D., Shen, F., Hu, J., Zeng, Y., & Huang, C. (2019). Valorizing waste lignocellulose-based furniture boards by phosphoric acid and hydrogen peroxide (Php) pretreatment for bioethanol production and high-value lignin recovery. Sustainability, 11(21), 6175.

    Article  CAS  Google Scholar 

  25. Lamers, P., Searcy, E., Hess, J. R., & Stichnothe, H. (Eds.). (2016). Developing the global bioeconomy: technical, market, and environmental lessons from bioenergy. Academic.

    Google Scholar 

  26. Sarkar, N., Ghosh, S. K., Bannerjee, S., & Aikat, K. (2012). Bioethanol production from agricultural wastes: An overview. Renewable Energy, 37(1), 19–27.

    Article  CAS  Google Scholar 

  27. Rojas-Chamorro, J. A., Romero, I., López-Linares, J. C., & Castro, E. (2020). Brewer’s spent grain as a source of renewable fuel through optimized dilute acid pretreatment. Renewable Energy, 148, 81–90.

    Article  CAS  Google Scholar 

  28. FAO. Yearbook of Forest Products 2015; Food and Agriculture Organization of the United Nations: London, UK, 2017; Vol. 2, pp. 397–467.

    Google Scholar 

  29. Pereira, S. R., & Sanchez i Nogue, V., Frazão, C.J., Serafim, L.S., Gorwa-Grauslund, M.F. and Xavier, A.M. (2015). Adaptation of Scheffersomyces stipitis to hardwood spent sulfite liquor by evolutionary engineering. Biotechnology for Biofuels, 8(1), 1–8.

    Article  CAS  Google Scholar 

  30. Gottumukkala, L. D., Haigh, K., Collard, F. X., Van Rensburg, E., & Görgens, J. (2016). Opportunities and prospects of biorefinery-based valorisation of pulp and paper sludge. Bioresource Technology, 215, 37–49.

    Article  CAS  PubMed  Google Scholar 

  31. Schroeder, B. G., Zanoni, P. R. S., Magalhães, W. L. E., Hansel, F. A., & Tavares, L. B. B. (2017). Evaluation of biotechnological processes to obtain ethanol from recycled paper sludge. Journal of Material Cycles and Waste Management, 19(1), 463–472.

    Article  CAS  Google Scholar 

  32. Nikolić, S., Lazić, V., Veljović, Đ, & Mojović, L. (2017). Production of bioethanol from pre-treated cotton fabrics and waste cotton materials. Carbohydrate Polymers, 164, 136–144.

    Article  PubMed  CAS  Google Scholar 

  33. Keshav, P. K., Shaik, N., Koti, S., & Linga, V. R. (2016). Bioconversion of alkali delignified cotton stalk using two-stage dilute acid hydrolysis and fermentation of detoxified hydrolysate into ethanol. Industrial Crops and Products, 91, 323–331.

    Article  CAS  Google Scholar 

  34. Wang, M., Zhou, D., Wang, Y., Wei, S., Yang, W., Kuang, M., Ma, L., Fang, D., Xu, S., & Du, S. K. (2016). Bioethanol production from cotton stalk: A comparative study of various pretreatments. Fuel, 184, 527–532.

    Article  CAS  Google Scholar 

  35. Singh, J., Sharma, A., Sharma, P., Singh, S., Das, D., Chawla, G., Singha, A., & Nain, L. (2020). Valorization of jute (Corchorus sp.) biomass for bioethanol production. Biomass Conversion and Biorefinery, pp.1–12.

    Google Scholar 

  36. Eurostat. Municipal Waste Statistics. http://appsso.eurostat.ec.europa.eu/nui/submitViewTableAction.do

  37. Tyagi, V. K., Fdez-Güelfo, L. A., Zhou, Y., Álvarez-Gallego, C. J., Garcia, L. R., & Ng, W. J. (2018). Anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW): Progress and challenges. Renewable and Sustainable Energy Reviews, 93, 380–399.

    Article  Google Scholar 

  38. Moreno, A. D., Magdalena, J. A., Oliva, J. M., Greses, S., Lozano, C. C., Latorre-Sánchez, M., Negro, M. J., Susmozas, A., Iglesias, R., Llamas, M., & Tomás-Pejó, E. (2021). Sequential bioethanol and methane production from municipal solid waste: An integrated biorefinery strategy towards cost-effectiveness. Process Safety and Environmental Protection, 146, 424–431.

    Article  CAS  Google Scholar 

  39. Chanoca, A., De Vries, L., & Boerjan, W. (2019). Lignin engineering in forest trees. Frontiers in Plant Science, 10, 912.

    Article  PubMed  PubMed Central  Google Scholar 

  40. Boerjan, W., Ralph, J., & Baucher, M. (2003). Lignin biosynthesis. Annual Review of Plant Biology, 54(1), 519–546.

    Article  CAS  PubMed  Google Scholar 

  41. Umezawa, T. (2018). Lignin modification in planta for valorization. Phytochemistry Reviews, 17(6), 1305–1327.

    Article  CAS  Google Scholar 

  42. Park, J. J., Yoo, C. G., Flanagan, A., Pu, Y., Debnath, S., Ge, Y., Ragauskas, A. J., & Wang, Z. Y. (2017). Defined tetra-allelic gene disruption of the 4-coumarate: Coenzyme A ligase 1 (Pv4CL1) gene by CRISPR/Cas9 in switchgrass results in lignin reduction and improved sugar release. Biotechnology for Biofuels, 10(1), 1–11.

    Article  CAS  Google Scholar 

  43. Yang, Y., Yoo, C. G., Guo, H. B., Rottmann, W., Winkeler, K. A., Collins, C. M., Gunter, L. E., Jawdy, S. S., Yang, X., Guo, H., & Pu, Y. (2017). Overexpression of a Domain of Unknown Function 266-containing protein results in high cellulose content, reduced recalcitrance, and enhanced plant growth in the bioenergy crop Populus. Biotechnology for Biofuels, 10(1), 1–13.

    CAS  Google Scholar 

  44. Vučurović, V. M., & Razmovski, R. N. (2012). Sugar beet pulp as support for Saccharomyces cerivisiae immobilization in bioethanol production. Industrial Crops and Products, 39, 128–134.

    Article  CAS  Google Scholar 

  45. Sindhu, R., Binod, P., Pandey, A., Madhavan, A., Alphonsa, J. A., Vivek, N., Gnansounou, E., Castro, E., & Faraco, V. (2017). Water hyacinth a potential source for value addition: An overview. Bioresource technology, 230, 152–162.

    Article  PubMed  CAS  Google Scholar 

  46. Huang, W. (2015). An integrated biomass production and conversion process for sustainable bioenergy. Sustainability, 7(1), 522–536.

    Article  Google Scholar 

  47. Rezania, S., Ponraj, M., Din, M. F. M., Songip, A. R., Sairan, F. M., & Chelliapan, S. (2015). The diverse applications of water hyacinth with main focus on sustainable energy and production for new era: An overview. Renewable and Sustainable Energy Reviews, 41, 943–954.

    Article  Google Scholar 

  48. Magdum, S., More, S., & Nadaf, A. (2012). Biochemical conversion of acid-pretreated water hyacinth (Eichhornia Crassipes) to alcohol using Pichia Stipitis NCIM3497. International Journal of advanced biotechnology and research, 3(2), 585–590.

    CAS  Google Scholar 

  49. Das, S., Bhattacharya, A., Haldar, S., Ganguly, A., Gu, S., Ting, Y. P., & Chatterjee, P. K. (2015). Optimization of enzymatic saccharification of water hyacinth biomass for bio-ethanol: Comparison between artificial neural network and response surface methodology. Sustainable Materials and Technologies, 3, 17–28.

    Article  CAS  Google Scholar 

  50. Malveaux, C. C. (2013). Coastal plants for biofuel production and coastal preservation.

    Google Scholar 

  51. Xu, J., Cui, W., Cheng, J. J., & Stomp, A. M. (2011). Production of high-starch duckweed and its conversion to bioethanol. Biosystems Engineering, 110(2), 67–72.

    Article  Google Scholar 

  52. Perniel, M., Ruan, R., & Martinez, B. (1998). Nutrient removal from a stormwater detention pond using duckweed. Applied Engineering in Agriculture, 14(6), 605–609.

    Article  Google Scholar 

  53. Cheng, J. J., & Stomp, A. M. (2009). Growing duckweed to recover nutrients from wastewaters and for production of fuel ethanol and animal feed. Clean-Soil, Air, Water, 37(1), 17–26.

    Article  CAS  Google Scholar 

  54. Zhao, X., Moates, G. K., Elliston, A., Wilson, D. R., Coleman, M. J., & Waldron, K. W. (2015). Simultaneous saccharification and fermentation of steam exploded duckweed: Improvement of the ethanol yield by increasing yeast titre. Bioresource Technology, 194, 263–269.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  55. Kollah, B., Patra, A. K., & Mohanty, S. R. (2016). Aquatic microphylla Azolla: A perspective paradigm for sustainable agriculture, environment and global climate change. Environmental Science and Pollution Research, 23(5), 4358–4369.

    Article  CAS  PubMed  Google Scholar 

  56. Miranda, A. F., Biswas, B., Ramkumar, N., Singh, R., Kumar, J., James, A., Roddick, F., Lal, B., Subudhi, S., Bhaskar, T., & Mouradov, A. (2016). Aquatic plant Azolla as the universal feedstock for biofuel production. Biotechnology for biofuels, 9(1), 1–17.

    Article  CAS  Google Scholar 

  57. Abdullahi, A. F., Maikaje, D. B., Denwe, S. D., & Muhammad, M. N. (2016). Evaluation of fermentation products of Eichhornia crassipes, Pistia stratiotes and Salvinia molesta. Agriculture and Biology Journal of North America, 7(1), 27–31.

    CAS  Google Scholar 

  58. Mohamad, N. R., Marzuki, N. H. C., Buang, N. A., Huyop, F., & Wahab, R. A. (2015). An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes. Biotechnology & Biotechnological Equipment, 29(2), 205–220.

    Article  CAS  Google Scholar 

  59. Kim, J., Grate, J. W., & Wang, P. (2006). Nanostructures for enzyme stabilization. Chemical engineering science, 61(3), 1017–1026.

    Article  CAS  Google Scholar 

  60. Srivastava, N., Singh, J., Ramteke, P. W., Mishra, P. K., & Srivastava, M. (2015). Improved production of reducing sugars from rice straw using crude cellulase activated with Fe3O4/Alginate nanocomposite. Bioresource technology, 183, 262–266.

    Article  CAS  PubMed  Google Scholar 

  61. Jordan, J., Kumar, C. S., & Theegala, C. (2011). Preparation and characterization of cellulase-bound magnetite nanoparticles. Journal of Molecular Catalysis B: Enzymatic, 68(2), 139–146.

    Article  CAS  Google Scholar 

  62. Hermanová, S., Zarevúcká, M., Bouša, D., Pumera, M., & Sofer, Z. (2015). Graphene oxide immobilized enzymes show high thermal and solvent stability. Nanoscale, 7(13), 5852–5858.

    Article  PubMed  CAS  Google Scholar 

  63. Kakaei, K., Rahimi, A., Husseindoost, S., Hamidi, M., Javan, H., & Balavandi, A. (2016). Fabrication of Pt–CeO2 nanoparticles supported sulfonated reduced graphene oxide as an efficient electrocatalyst for ethanol oxidation. International Journal of Hydrogen Energy, 41(6), 3861–3869.

    Article  CAS  Google Scholar 

  64. Kim, Y. K., Park, S. E., Lee, H., & Yun, J. Y. (2014). Enhancement of bioethanol production in syngas fermentation with Clostridium ljungdahlii using nanoparticles. Bioresource Technology, 159, 446–450.

    Article  CAS  PubMed  Google Scholar 

  65. Kim, Y. K., & Lee, H. (2016). Use of magnetic nanoparticles to enhance bioethanol production in syngas fermentation. Bioresource Technology, 204, 139–144.

    Article  CAS  PubMed  Google Scholar 

  66. Ivanova, V., Petrova, P., & Hristov, J. (2011). Application in the ethanol fermentation of immobilized yeast cells in matrix of alginate/magnetic nanoparticles, on chitosan-magnetite microparticles and cellulose-coated magnetic nanoparticles. arXiv preprint arXiv:1105.0619.

  67. Santos, F. C. U., Paim, L. L., da Silva, J. L., & Stradiotto, N. R. (2016). Electrochemical determination of total reducing sugars from bioethanol production using glassy carbon electrode modified with graphene oxide containing copper nanoparticles. Fuel, 163, 112–121.

    Article  CAS  Google Scholar 

  68. Lin, L., Liu, T., Zhang, Y., Liang, X., Sun, R., Zeng, W., & Wang, Z. (2016). Enhancing ethanol detection by heterostructural silver nanoparticles decorated polycrystalline zinc oxide nanosheets. Ceramics International, 42(2), 3138–3144.

    Article  CAS  Google Scholar 

  69. Abraham, R. E., Verma, M. L., Barrow, C. J., & Puri, M. (2014). Suitability of magnetic nanoparticle immobilised cellulases in enhancing enzymatic saccharification of pretreated hemp biomass. Biotechnology for biofuels, 7(1), 1–12.

    Article  CAS  Google Scholar 

  70. Miao, X., Pi, L., Fang, L., Wu, R., & Xiong, C. (2016). Application and characterization of magnetic chitosan microspheres for enhanced immobilization of cellulase. Biocatalysis and Biotransformation, 34(6), 272–282.

    Article  CAS  Google Scholar 

  71. Su, T. C., Fang, Z., Zhang, F., Luo, J., & Li, X. K. (2015). Hydrolysis of selected tropical plant wastes catalyzed by a magnetic carbonaceous acid with microwave. Scientific Reports, 5(1), 1–14.

    Article  Google Scholar 

  72. Baskar, G., Kumar, R. N., Melvin, X. H., Aiswarya, R., & Soumya, S. (2016). Sesbania aculeate biomass hydrolysis using magnetic nanobiocomposite of cellulase for bioethanol production. Renewable Energy, 98, 23–28.

    Article  CAS  Google Scholar 

  73. Ingle, A. P., Rathod, J., Pandit, R., da Silva, S. S., & Rai, M. (2017). Comparative evaluation of free and immobilized cellulase for enzymatic hydrolysis of lignocellulosic biomass for sustainable bioethanol production. Cellulose, 24(12), 5529–5540.

    Article  CAS  Google Scholar 

  74. Cherian, E., Dharmendirakumar, M., & Baskar, G. (2015). Immobilization of cellulase onto MnO2 nanoparticles for bioethanol production by enhanced hydrolysis of agricultural waste. Chinese Journal of Catalysis, 36(8), 1223–1229.

    Article  CAS  Google Scholar 

  75. Mishra, A., & Sardar, M. (2015). Cellulase assisted synthesis of nano-silver and gold: Application as immobilization matrix for biocatalysis. International Journal of Biological Macromolecules, 77, 105–113.

    Article  CAS  PubMed  Google Scholar 

  76. Sanusi, I. A., Faloye, F. D., & Gueguim Kana, E. B. (2019). Impact of various metallic oxide nanoparticles on ethanol production by Saccharomyces cerevisiae BY4743: Screening, kinetic study and validation on potato waste. Catalysis Letters, 149(7), 2015–2031.

    Article  CAS  Google Scholar 

  77. Sanusi, I. A., Suinyuy, T. N., Lateef, A., & Kana, G. E. (2020). Effect of nickel oxide nanoparticles on bioethanol production: Process optimization, kinetic and metabolic studies. Process Biochemistry, 92, 386–400.

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Microbiology, Kurukshetra University, Kurukshetra, Haryana, India

    Neeraj K. Aggarwal, Naveen Kumar & Mahak Mittal

Authors
  1. Neeraj K. Aggarwal
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Naveen Kumar
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Mahak Mittal
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Neeraj K. Aggarwal .

Rights and permissions

Reprints and permissions

Copyright information

© 2022 The Author(s), under exclusive license to Springer Nature Switzerland AG

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Aggarwal, N.K., Kumar, N., Mittal, M. (2022). A Feasible Approach for Bioethanol Production Using Conventional and New Feedstocks. In: Bioethanol Production. Green Chemistry and Sustainable Technology. Springer, Cham. https://doi.org/10.1007/978-3-031-05091-6_4

Download citation

Publish with us

Policies and ethics

Search

Navigation