Andrea Komesu

Purification of Lactic Acid Produced by Fermentation: Focus on Non-traditional Distillation Processes

Lactic acid is commonly used in a wide range of fields such as cosmetics, pharmaceutical products, chemistry and food. During the last years, its use for new applications such as production of biodegradable and biocompatible polymers, green solvents and oxygenated chemicals have received considerable attention. However, the relatively high production cost of lactic acid hinders many large-scale applications. In order to cheapen lactic acid production processes, it is necessary to develop more efficient methods of separation and purification. This work reviews some promising non-traditional distillation processes that are currently employed for lactic acid recovery, focusing on reactive distillation and molecular distillation. Advances in such distillation-based processes, their drawbacks and concluding remarks are also presented.

The Effect of Evaporator Temperature on Lactic Acid Purity and Recovery by Short Path Evaporation

In this work, the evaluation of lactic acid concentration from a synthetic mixture of water and lactic acid (3 wt% of lactic acid) was carried out using short path evaporation (SPE). The evaporator temperature of a SPE is one of the important technological parameters that determine an evaporator’s operation. In this study, the effect of the evaporator temperature on the lactic acid purity and recovery was observed from 303 to 443 K. The results showed that, in the studied range, the evaporator temperature of 353 K can be regarded as the best, since an increase of 2.15 times in the solution concentration was obtained.

Nanotechnology Applications on Lignocellulosic Biomass Pretreatment

Global population growth raises questions concerning the environment and energy production. Fossil fuels are well known and utilized energy source. These are not renewable and contribute to the greenhouse gas effect. The search for alternative energy sources and solution for environmental problems has a growing concern in recent years. The lignocellulosic biomass has emerged as a solution to our energy and environmental concerns since it is rich within feedstock and can be converted to biofuels and/or biomaterials. This approach is interesting because these biomasses can become renewable sources of energy and pollute less than fossil fuels when transformed into biofuels, which is a green fuel. However, some steps are necessary to transform these lignocellulosic biomasses into biofuels or biomaterials. Nanotechnology is a multidisciplinary area of study with several applications that can be used to improve the lignocellulose bioconversion process, used both in production of liquid fuels through conversion by fermentation, gasification, or catalysis and development of new nanoscale catalyzers/materials. Nanoscale or sub-nanoscale instrumentation facilitates understanding of the lignocellulosic biomass cell wall ultrastructure and enzymatic mechanisms. This aspect contributes in the development of sophisticated instrumentation techniques for lignocellulosic fiber analysis such as scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), and atomic force microscopy (AFM).

Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

Actually, there is a growing interest in the biotechnological production of lactic acid by fermentation aiming to substitute fossil fuel routes. The development of an efficient method for its separation and purification from fermentation broth is very important to assure the economic viability of production. Due to its high reactivity and tendency to decompose at high temperatures, the study of lactic acid thermal behavior is essential for its separation processes and potential application. In the present study, differential scanning calorimetry (DSC) analyses showed endothermic peaks related to the process of evaporation. Data of thermogravimetry (TG/DTG) were correlated to Arrhenius and Kissinger equations to provide the evaporation kinetic parameters and used to determine the vaporization enthalpy. Activation energies were 51.08 and 48.37 kJ·mol−1 and frequency values were 859.97 and 968.81 s−1 obtained by Arrhenius and Kissinger equations, respectively. Thermogravimetry, coupled with mass spectroscopy (TG-MS), provided useful information about decomposition products when lactic acid was heated at 573 K for approximately 30 min.

Separation of Lactic Acid from Diluted Solution by Hybrid Short Path Evaporation and Reactive Distillation

This work describes the separation and purification of lactic acid from diluted solution by HSPE (hybrid short path evaporation) and RD (reactive distillation) as coupled process. The results showed that it is possible to increase lactic acid concentration up to 4.7 times higher than the raw material concentration.

Simulation of Molecular Distillation Process for Lactic Acid

In this work, a procedure to simulate the MD (molecular distillation) process for lactic acid purification was developed. The simulation was carried out with the aid of the Aspen Plus Process Simulator. Flash vessel was used to represent the MD process since the software does not present this unit operation. The simulation results with efficiency factors were in agreement with previously reported experimental data.