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| Author(s): |
Regiane Alves de Oliveira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia de Alimentos |
| Defense date: | 2019-06-25 |
| Examining board members: |
Rubens Maciel Filho;
Marcus Bruno Soares Forte;
Sindelia Freitas;
Betânia Hoss Lunelli
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| Advisor: | Carlos Eduardo Vaz Rossell; Rubens Maciel Filho |
| Abstract | |
Lactic acid is an organic acid that has a wide range of well-established industrial applications, such as in the food, pharmaceutical, and cosmetic industries. New applications are frequently discovered and released in the market. Currently, its most highlighted applications are related to the medical industry, production of polymers - biodegradable or not - and its use as a building-block molecule for the production of other molecules in the chemical industry. This work presents the main aspects related to the production and separation/purification of first and second-generation lactic acid produced from sugarcane, considering upstream, downstream, market trends, perspectives, and challenges. Initially, it was performed a screening of microorganisms that resulted in the selection of a Lactobacillus plantarum strain to be used for the production of first and second-generation lactic acid. Sugarcane molasses is a rich nutritional source for the production of first-generation lactic acid. For countries where sugar cane is an important crop, its use may open up an opportunity for the implementation of a biorefinery that produces sugar, ethanol, yeast, electricity and lactic acid, as it has been done in the sugar and alcohol sectors. Using molasses as a substrate, it was produced 157.9 g/L of lactic acid, with a productivity of 5.4 g L-1 h-1 and a 95 % yield. Second-generation lactic acid was produced from the hemicellulosic fraction of hydrolyzed sugarcane bagasse. Using L. plantarum, it was obtained 34.5 g/L of lactic acid. This study also detected a phenomenon called bio-detoxification, in which the microorganism is not affected by the remaining inhibitors from the bagasse pretreatment, and it was able to decrease the concentrations of furfural and HMF by 98 % and 86 %, respectively. In order to increase the production of lactic acid, a strain of Bacillus coagulans was selected to produce lactic acid from the hemicellulosic fraction of the sugarcane bagasse. It produced 60.0 g/L of lactic acid, with a productivity of 1.7 g L 1 h-1 and 87 % of yield. This microorganism also showed the ability to bio-detoxify the fermentation broth, removing 100 % of the furfural and HMF present in the hydrolysate. Considering alternative processes of separation and purification of lactic acid, there are still several challenges to be overcome. Hybrid short path evaporation (HSPE) may be an alternative method for the recovery and purification of lactic acid, reducing the risk of thermal decomposition of molecules and avoiding the use of toxic solvents. It is an ecologically correct and balanced technique, with the scope and potential of the large-scale application. Front these reasons, HSPE was tested as an alternative method to the traditional process of lactic acid downstream. Using a fermentation broth from molasses, it was possible to reach a lactic acid concentration of 247.7 g/L, equivalent to 2.5 times higher than the initial fermentation broth (100.1 g/L). For second-generation lactic acid produced from hemicellulosic hydrolysate, it was achieved a maximum lactic acid concentration of 86.7 g/L, which is equivalent to 3.1 times the lactic acid concentration in the feed stream (27.9 g/L). In both cases, the results showed that all studied variables influenced the process: evaporator temperature, internal condenser temperature, and feed flow rate. These studies allowed the identification of different challenges in the separation of first and second-generation lactic acid. Finally, future research should focus on the study of more efficient and sustainable downstream techniques, both for first and second-generation lactic acid. It is also necessary assessing the economic implications for the sugar and ethanol industries’ of implementing a biorefinery that would also produce lactic acid from sugarcane. This is fundamental for the implementation of first and second-generation lactic acid production in the Brazilian market (AU) | |
| FAPESP's process: | 13/26290-5 - Optimization of lactic acid production from sugar cane |
| Grantee: | Regiane Alves de Oliveira |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |