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Lactic acid has been shown to have the most promising application in biomaterials as poly(lactic acid). L. rhamnosus ATCC 10863 that produces L-lactic acid was used to perform the fermentation and molasses was used as substrate. A solution containing 27.6 g/L of sucrose (main composition of molasses) and 3.0 g/L of yeast extract was prepared, considering the final volume of 3,571 mL (14.0% (v/v) inoculum). Batch and fed batch fermentations were performed with temperature of 43.4°C and pH of 5.0. At the fed batch, three molasses feed were applied at 12, 24, and 36 hours. Samples were taken every two hours and the amounts of lactic acid, sucrose, glucose, and fructose were determined by HPLC. The sucrose was barely consumed at both processes; otherwise the glucose and fructose were almost entirely consumed. 16.5 g/L of lactic acid was produced at batch and 22.0 g/L at fed batch. Considering that lactic acid was produced due to the low concentration of the well consumed sugars, the final amount was considerable. The cell growth was checked and no substrate inhibition was observed. A sucrose molasses hydrolysis is suggested to better avail the molasses fermentation with this strain, surely increasing the L-lactic acid.

Lactic acid is an important product arising from the anaerobic fermentation of sugars. It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. In this work, several bacterial strains were isolated from industrial ethanol fermentation, and the most efficient strain for lactic acid production was selected. The fermentation was conducted in a batch system under anaerobic conditions for 50 h at a temperature of 34 degrees C, a pH value of 5.0, and an initial sucrose concentration of 12 g/L using diluted sugarcane molasses. Throughout the process, pulses of molasses were added in order to avoid the cell growth inhibition due to high sugar concentration as well as increased lactic acid concentrations. At the end of the fermentation, about 90% of sucrose was consumed to produce lactic acid and cells. A kinetic model has been developed to simulate the batch lactic acid fermentation results. The data obtained from the fermentation were used for determining the kinetic parameters of the model. The developed model for lactic acid production, growth cell, and sugar consumption simulates the experimental data well.

Lactic acid (LA) production is already a global reality. Its applications cover the most diverse industrial sectors and have rapidly consolidated in recent years. Currently, the most prominent use of LA is the production of polylactic acid to replace plastics from the petrochemical industry. A great part of this rapid change is due to the rising worldwide concerns about the excess of non-degradable plastics used daily and the accumulation of this material in nature. In this scenario, LA production becomes even more relevant when considering its production from renewable raw materials, especially second-generation (2G) substrates, such as lignocellulosic biomass. This reduces the human dependence on oil for both energy and fuel production, as well as for the production of plastics and other chemicals since LA is still one of the most relevant building block chemicals. Nowadays it is possible to produce LA from the most diverse 2G-substrates available around the world. Thus, LA production by fermentation of 2G-sugars can be associated with several existing biorefinery models, such as for biofuels and chemicals production. In this scenario, for example, it is possible to associate LA production with ethanol production in a biorefinery model, producing 1G-ethanol, 2G-LA, sugar for food, and electricity. This kind of approach may represent a break from current production model of energy and chemicals to a more sustainable and democratic scenario, including new players in the world market and reducing the dependence of other countries to supply oil and its derivates, especially when associated with new and powerful genetic engineering tools. Front this scenario, this review presents the state of the art of 2G-LA production. [ABSTRACT FROM AUTHOR]

Lactic acid is an important chemical as starting chiral material in various applications. It has increased value in the global market. Different studies have presented the possibility to obtain rich lactic acid solutions with high isomeric purity (S-form) from second-generation (2G) feedstocks. The used downstream process is crucial, not only in terms of the overall cost but also for the achievement of high product purity, suitable for high-value applications. This review provides an overview of the current state-of-the-art on the separation and purification methods of lactic acid derived from the fermentation of second-generation feedstocks. The traditional precipitation method, solvent extraction, affinity-related processes, membrane separation, reaction-separation systems, salting-out extraction and molecular distillation are the main processes investigated so far. The different approaches are discussed in terms of lactic acid recovery yield and purity as well as their environmental impact. [ABSTRACT FROM AUTHOR]

Lactic acid is an important platform chemical with a wide range of applications. Production of lactic acid by fermentation is advantageous because renewable and low cost raw materials can be used as substrates. After fermentation, the broth needs to be purified to obtain pure lactic acid for further uses. Thus, efficient downstream processes are very important because they account for 50% of the production costs. This review discusses different processes that are currently employed for lactic acid recovery, focusing on precipitation, solvent extraction, and separation with membranes. Advances in such recovery processes and drawbacks that limit the application of these technologies at the industrial level are also presented. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Short path evaporation (SPE) is a promising separation technique for the purification of lactic acid from fermentation broth. This study investigated the influence of residual sugars, such as glucose, xylose, and sucrose, on the purification of lactic acid using SPE. A 23 factorial experimental design was performed in the experimental range from 5 g.L-1 to 15 g.L-1 for glucose, xylose, and sucrose concentrations. Glucose and sucrose concentrations did not have significant effects on the process of lactic acid concentration in the range used for this study. Xylose in high concentration was found to reduce the lactic acid concentration process performance. An increase in the boiling temperature of the mixture by the ebullioscopy effect possibly hindered the evaporation of the mixture. [ABSTRACT FROM AUTHOR]

Lactic acid is a naturally occurring organic acid that can be used in a wide variety of industries, such as the cosmetic, pharmaceutical, chemical, food, and, most recently, the medical industries. It can be made by the fermentation of sugars obtained from renewable resources, which means that it is an eco-friendly product that has attracted a lot of attention in recent years. In 2010, the U.S. Department of Energy issued a report that listed lactic acid as a potential building block for the future. Bearing the importance of lactic acid in mind, this review summarizes information about lactic acid properties and applications, as well as its production and purification processes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Lactic acid has been shown to have the most promising application in biomaterials as poly(lactic acid). L. rhamnosus ATCC 10863 that produces L-lactic acid was used to perform the fermentation and molasses was used as substrate. A solution containing 27.6 g/L of sucrose (main composition of molasses) and 3.0 g/L of yeast extract was prepared, considering the final volume of 3,571 mL (14.0% (v/v) inoculum). Batch and fed batch fermentations were performed with temperature of 43.4°C and pH of 5.0. At the fed batch, three molasses feed were applied at 12, 24, and 36 hours. Samples were taken every two hours and the amounts of lactic acid, sucrose, glucose, and fructose were determined by HPLC. The sucrose was barely consumed at both processes; otherwise the glucose and fructose were almost entirely consumed. 16.5 g/L of lactic acid was produced at batch and 22.0 g/L at fed batch. Considering that lactic acid was produced due to the low concentration of the well consumed sugars, the final amount was considerable. The cell growth was checked and no substrate inhibition was observed. A sucrose molasses hydrolysis is suggested to better avail the molasses fermentation with this strain, surely increasing the L-lactic acid. [ABSTRACT FROM AUTHOR]

Lactic acid is a high-value molecule with a vast number of applications. Its production in the biorefineries model is a possibility for this sector to aggregate value to its production chain. Thus, this investigation presents a biorefinery model based on the traditional sugar beet industry proposing an approach to produce lactic acid from a waste stream. Sugar beet is used to produce sugar and ethanol, and the remaining pulp is sent to animal feed. Using Bacillus coagulans in a continuous fermentation, 2781.01 g of lactic acid was produced from 3916.91 g of sugars from hydrolyzed sugar beet pulp, with a maximum productivity of 18.06 g L−1h−1. Without interfering in the sugar production, ethanol, or lactic acid, it is also possible to produce pectin and phenolic compounds in the biorefinery. The lactic acid produced was purified by a bipolar membrane electrodialysis and the recovery reached 788.80 g/L with 98% w/w purity. [ABSTRACT FROM AUTHOR]

In this work, lactic acid purification by short path evaporation (SPE) was evaluated using central composite experimental design. The influences of the evaporator temperature (from 86.7 to 177.3 °C) and condenser temperature (from 7.5 to 24.5 °C) on distilled percentage, and lactic acid purity and recovery at the distillate stream were studied. In the range of study, lactic acid purity obtained at 1 kPa, using evaporator temperature of 86.7 °C and condenser temperature of 16 °C presented the highest lactic acid purity which was about 11 times lactic acid concentration higher than the initial content in raw material. [ABSTRACT FROM AUTHOR]

Highlights • Separation of lactic acid from 5-carbon sugars is more difficult than from 6-carbon sugars. • Lactic acid concentration is influenced by internal condenser temperature, evaporator temperature, and feed flow rate. • Presence of sugars from fermentation hinder lactic acid separation via hybrid short path evaporation. Abstract Production of lactic acid (LA) from lignocellulosic materials has become increasingly prominent in the market. However, for industrial scale to be reached, several challenges in second-generation lactic acid production must be overcome. Besides obstacles such as the hydrolysis process, one of the major challenges of the lactic acid industry is the separation and purification process. This study evaluates the separation of lactic acid produced from hemicellulose hydrolysate from sugarcane bagasse using a Hybrid Short Path Evaporation (HSPE) system. Results showed that a lactic acid concentration of 3.1 times the feed concentration (27.85 g/L) is achievable. Three operational parameters were studied: evaporator temperature, internal condenser temperature and feed flow rate. Maximum lactic acid concentration was 86.69 g/L with an evaporator temperature of 120 °C, condenser temperature of 13 °C, and feed flow rate of 8.27 mL/min. Separation of LA from hemicellulosic sugars using HSPE was a more difficult process than separation of LA from 6-carbon sugars. [ABSTRACT FROM AUTHOR]

Furfural and HMF are known for a negative impact in different bioprocesses, including lactic acid fermentation. There are already some methods described to remove these inhibitory compounds from the hydrolysates. However, these methods also reduce the yield of sugars from the hydrolysis and increase the process costs. In this work, the detoxification of sugarcane-derived hemicellulosic hydrolysate was performed by Lactobacillus plantarum during the fermentation time. At the end of the fermentation, a decrease of 98% of furfural and 86% of HMF and was observed, with a final lactic acid titer of 34.5 g/L. The simultaneous fermentation and bio-detoxification simplify the process and reduce operational costs, leading to economic competitiveness of second-generation feedstock for lactic acid production. [ABSTRACT FROM AUTHOR]

Lactic acid is an already consolidated bioproduct in the world market. It has many applications, such as: the production of biodegradable polymers, substitution of plastics from oil, and new uses in medicine. Besides this, new applications are being discovered every year, especially in chemical industries as a building-block molecule. The lactic acid market is in constant growth and the fact that the final products are able to comply with environmental laws as green, renewable and biodegradable products contributes to the tendency of continuous growth in the next few years. With all of this in mind, this paper will explore the main aspects of the sector, as well as market tendencies, production chain, and innovation. [ABSTRACT FROM AUTHOR]

This work describes the evaluation of lactic acid purification from fermentation broth by hybrid short path evaporation. The proposed hybrid purification process consists of an evaporation system composed by a cylindrical wiped film evaporator with two condensers, one located internally and other externally to the evaporator. Through factorial experimental design, the influence of operation conditions as feed flow rate, agitation, condenser and evaporator temperature on residue and distilled percentages, lactic acid purity and recovery were studied. Models were developed in order to describe the response of interest as function of operating conditions. The results showed that with a high operating pressure (in terms of short path evaporation), with a pressure of 1000 Pa, and one step of separation, lactic acid purity around 89.7% was obtained which was about 18 times lactic acid concentration higher than the initial content in raw material. [ABSTRACT FROM AUTHOR]

• Sugarcane bagasse cellulose hydrolysate contained 13 g/L lactic acid. • Sugarcane molasses was used as a source of nutrients and buffering capacity. • Clostridium beijerinckii DSM 6423 was able to consume up to 92% of the lactic acid. • Lactic acid was preferentially metabolized to butanol. • Sucrose, glucose, fructose, xylose, and lactic acid were co-fermented. Enzymatic hydrolysis of lignocellulose under industrial conditions is prone to contamination by lactic acid bacteria, and in this study, a cellulose hydrolysate produced from dilute-acid pretreated sugarcane bagasse contained 13 g/L lactic acid and was used for IBE production by Clostridium beijerinckii DSM 6423. In fermentation of the cellulose hydrolysate supplemented with sugarcane molasses for nutrients and buffering of the medium (40 g/L total sugar), 92% of the lactic acid was consumed, and the butanol yield was as high as 0.28 (7.9 g/L butanol), suggesting that lactic acid was preferentially metabolized to butanol. When the hydrolysate was mixed with a detoxified bagasse hemicellulose hydrolysate and supplemented with molasses (35 g/L total sugar), the culture was able to exhaust glucose and utilized sucrose (by 38%), xylose (31%), and lactic acid (70%). Overall, this study shows that C. beijerinckii DSM 6423 can co-ferment first- and second-generation sugars while consuming lactic acid. [ABSTRACT FROM AUTHOR]