Lactic Acid Production Yield Research Articles

Physicochemical Characterization of Potassium Hydroxide Pretreated Chestnut Shell and Its Bioconversion to Lactic Acid by Lacticaseibacillus rhamnosus

Lactic acid (LA) is an important platform chemical with a wide range of applications, including bioplastic materials, and demand for it is growing rapidly. However, the high cost of feedstock for LA production is a major barrier to industrial production. This study designed a process to produce LA from chestnut shell (CS), a low-cost biomass. The entire process includes KOH pretreatment, enzymatic saccharification, and fermentation. This study investigated the chemical compositions and physicochemical properties of raw CS and KOH pretreated CS (KpCS) to evaluate the impact of the pretreatment process that enhances the conversion of cellulose into glucose. The results showed that KOH affected the lignin removal and surface morphological changes of CS, and FT-IR and TGA patterns correlated to increased cellulose fractions were found. In the fermentation process, Lacticaseibacillus rhamnosus was selected as a prominent LA producer, and the fermentation using KpCS hydrolysate was carried out. As a result, cell growth (27%), glucose consumption (23%), and LA production (21%) were all achieved higher than the control group. The LA production yield from our suggested process was estimated to be 187 g/kg CS, and we concluded that CS has a high potential as a feedstock for LA production.

L-lactate production in engineered Saccharomyces cerevisiae using a multistage multiobjective automated design framework.

The design of alternative biodegradable polymers has the potential of severely reducing the environmental impact, cost and production time currently associated with the petrochemical industry. In fact, growing demand for renewable feedstock has recently brought to the fore synthetic biology and metabolic engineering. These two interdependent research areas focus on the study of microbial conversion of organic acids, with the aim of replacing their petrochemical-derived equivalents with more sustainable and efficient processes. The particular case of Lactic acid (LA) production has been the subject of extensive research because of its role as an essential component for developing an eco-friendly biodegradable plastic-widely used in industrial biotechnological applications. Because of its resistance to acidic environments, among the many LA-producing microbes, Saccharomyces cerevisiae has been the main focus of research into related biocatalysts. In this study, we present an extensive in silico investigation of S. cerevisiae cell metabolism (modeled with Flux Balance Analysis) with the overall aim of maximizing its LA production yield. We focus on the yeast 8.3 steady-state metabolic model and analyze it under the impact of different engineering strategies including: gene knock-in, gene knock-out, gene regulation and medium optimization; as well as a comparison between results in aerobic and anaerobic conditions. We designed ad-hoc constrained multiobjective evolutionary algorithms to automate the engineering process and developed a specific postprocessing methodology to analyze the genetic manipulation results obtained. The in silico results reported in this paper empirically show that our method is able to automatically select a small number of promising genetic and metabolic manipulations, deriving competitive strains that promise to impact microorganisms design in the production of sustainable chemicals.

The dissolution of polysaccharides and amino acids enhanced lactic acid production from household food waste during pretreatment process

A large amount of household food waste (HFW) is produced yearly, resulting in environmental problems and financial burdens. Bio-production of lactic acid (LA), a high value-added platform chemical, from HFW by anaerobic fermentation is a promising way of resource recovery. However, the LA production yield from HFW is low. This paper compared several pretreatment methods (hydrothermal pretreatment, chemical pretreatment, and combined hydrothermal and chemical pretreatment) to improve LA production from HFW. The result showed that the combined pretreatment (alkali-thermal pretreatment at pH 10 and 120 °C) significantly increased the LA production than single hydrothermal and chemical pretreatment. The pretreatment process promoted the dissolution of organics, especially the polysaccharides and amino acids, and further influenced the LA production by Lactobacillus rhamnosus ATCC 7469. Among the amino acids, aspartic acid (Asp), threonine (Thr), glutamic acid (Glu), glycine (Gly), alanine (Ala), cystine (Cys), valine (Val), isoleucine (Ile), arginine (Arg), and proline (Pro) significantly correlated with LA concentration.

해조류 바이오매스로부터 Lactic acid를 제조하는 방법에 관한 연구

With the spread of COVID-19 worldwide, non-face-to-face services have grown rapidly, but at the same time, the problem of plastic waste is getting worse. Accordingly, eco-friendly policies such as carbon neutrality and sustainable circular economy are being promoted worldwide. Due to the high demand for eco-friendly products, the packaging industry is trying to develop eco-friendly packaging materials using PLA and PBAT and create new business models. On the other hand, Ulva australis occurs in large quantities in the southern seas of Korea and off the coast of Jeju Island, causing marine environmental problems. In this study, lactic acid was produced through dilute acid pretreatment, enzymatic saccharification, and fermentation processes to utilize Ulva australis as a new alternative energy raw material. In general, seaweeds vary in carbohydrate content and sugar composition depending on the species, harvest location, and time. Seaweed is mainly composed of polysaccharides such as cellulose, alginate, mannan, and xylan, but does not contain lignin. It is difficult to expect high extraction yield of the complex polysaccharide constituting Ulva australis with only one process. However, the fusion process of dilute acid and enzymatic saccharification presented in this study can extract most of the sugars contained in Ulva australis. Therefore, the fusion process is considered to be able to expect high lactic acid production yield when a commercial-scale production process is established.

Effect of initial pH and substrate concentration on the lactic acid production from cassava wastewater fermentation by an enriched culture of acidogenic microorganisms.

Recently, cassava processing wastewater has been considered an alternative substrate for lactic acid production due to its appreciable carbohydrate levels. The authors carried out different batch reactor trials aiming to favor the production of lactic acid through the fermentation of non-sterilized cassava wastewater by an enriched culture of acidogenic microorganisms. To this end, the impact of different initial pHs (4.5, 5.0, 5.7, 6.5, and 7.0) and different initial substrate concentrations (10, 15.8, 30, 44.2, and 50g/L) in terms of glucose on lactic acid production yield (Y) was evaluated by applying the design of experiment (DoE) known as central composite rotatable design (CCRD). The highest rate of lactic acid production (40g/L) occurred with an initial pH of 6.5 and an initial substrate concentration of 50g/L. The maximum yield was higher in trials T1, T2, T4, T5, and T8, reaching values of 0.80, 0.62, 0.60, 0.96, and 0.70g/g, respectively. The maximum lactic acid productivity (P), of 0.60 and 0.73gL-1 hr-1 , was observed in trials T5 and T8, respectively. The enriched culture of acidogenic microorganisms was shown to favor the production of lactic acid, since the production of other acids, such as acetic and propionic acid, did not exceed 3.5 and 4.5g/L, respectively. © 2020 Water Environment Federation PRACTITIONER POINTS: Cassava wastewater presented potential to lactic acid production. The CCRD showed that highest lactic acid concentrations (40g/L). The adoption of cassava wastewater or manipueira as a substrate resulted in important information on the tendency to obtain value-added products such as lactic acid.

Lactic Acid Production from High Concentration of Invert Sugar in Semi-Batch Reactor

The objective in this study is the production of high yield of lactic acid production from invert sugar in alkaline degradation at mild reaction condition. The invert sugar was immediately and continuously added into an alkaline solution in a batch and semi-batch reactor, respectively. The effect of batch and semi-batch, initial concentration of sodium hydroxide and initial of concentrated raw materials were studied. Semi-batch provided better yield than batch reactor. High sodium hydroxide concentration with low invert sugar in semi-batch operation was found to have high lactic acid. The feed concentration of invert sugar at 30, 45 and 70% provided lactic acid yield around 65-68% for excess sodium hydroxide base at 50°C and 10 hr.

Anaerobic Acidification of Coconut Water Waste by Lactobacillus acidophilus Culture for Biotechnological Production of Lactic Acid

The biotechnological production of lactic acid could be carried out via anaerobic acidification process. In order to achieve an optimal production of lactic acid, the role of inoculum would be essential. The current study aimed to investigate as well as evaluate the effect of inoculum concentration on the anaerobic acidification of coconut water waste for the production of lactic acid. Results showed that the addition of 20% inoculums to the reactor fermenting coconut water waste was sufficient for the optimal production of lactic acid. In the batch process anaerobic acidification of coconut water waste inoculated with 20% inoculums of Lactobacillus acidophilus culture had the yield of lactic acid production, which was about 1.62 mmol lactic acid/mmol glucose while under the continuous operation the yield of lactic acid production obtained, was about 1.15 mmol lactic acid/mmol glucose. During the acidification process in both batch and continuous modes pH dropped significantly from 5.1 to 3.7.

Growth kinetic models of five species of Lactobacilli and lactose consumption in batch submerged culture.

Kinetic behaviors of five Lactobacillus strains were investigated with Contois and Exponential models. Awareness of kinetic behavior of microorganisms is essential for their industrial process design and scale up. The consistency of experimental data was evaluated using Excel software. L. bulgaricus was introduced as the most efficient strain with the highest biomass and lactic acid yield of 0.119 and 0.602 g g−1 consumed lactose, respectively. The biomass and carbohydrate yield of L. fermentum and L. lactis were slightly less and close to L. bulgaricus. Biomass and lactic acid production yield of 0.117 and 0.358 for L. fermentum and 0.114 and 0.437 g g−1 for L.actobacillus lactis were obtained. L. casei and L. delbrueckii had the less biomass yield, nearly 11.8 and 22.7% less than L. bulgaricus, respectively. L. bulgaricus (R2 = 0.9500 and 0.9156) and L. casei (R2 = 0.9552 and 0.8401) showed acceptable consistency with both models. The investigation revealed that the above mentioned models are not suitable to describe the kinetic behavior of L. fermentum (R2 = 0.9367 and 0.6991), L. delbrueckii (R2 = 0.9493 and 0.7724) and L. lactis (R2 = 0.8730 and 0.6451). Contois rate equation is a suitable model to describe the kinetic of Lactobacilli. Specific cell growth rate for L. bulgaricus, L. casei, L. fermentum, L. delbrueckii and L. lactis with Contois model in order 3.2, 3.9, 67.6, 10.4 and 9.8-fold of Exponential model.

Selection of the Strain Lactobacillus acidophilus ATCC 43121 and Its Application to Brewers' Spent Grain Conversion into Lactic Acid.

Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source.

A study on Lactic Acid fermentation of Sugar Palm (Arenga Pinnata) sap by Lactobacillus Casei

This study aimed to evaluate the effect of various factors on the yield of lactic acid fermentation using sap from sugar palm and Lactobacillus casei. The sugar palm sap after harvesting, pretreatment was added with ammonium sulphate, calcium carbonate and microbial culture at density of 109 cells/ml and let fermented for acid lactic production. The results of the experiments showed that the culture size, amount of added ammonium sulphate and calcium carbonate had significant effect on lactic acid production. The most appropriate parameters determined were culture size of 5%, ammonium sulphate of 3.0 g/l and calcium carbonate of 4.0 g/l. Meanwhile, the optimum period of fermentation was 100 h, which gave the yield of lactic acid production of 22.30 g. Lactobacillus casei was considered to have lower ability to effectively produce lactic acid from sugar palm sap compared to Lactobacillus plantarum

Molecular characterisation and biomass and metabolite production of Lactobacillus reuteri LPB P01-001: A potential probiotic.

Lactobacillus reuteri LPB P01–001 was isolated from the gastrointestinal tract of wild swine and was characterised by biochemical testing and sequencing of gene 16S rRNA. A simple and low-cost culture medium based on cane sugar (2.5% p/v) and yeast extract (1% p/v) was used in the production of this probiotic. The fermentative conditions were a) pH control at 6.5 and b) no pH control; both were set at 37°C in a 12 L slightly stirred tank bioreactor. Fermentation parameters such as the specific growth rate, productivity and yield of biomass, lactic and acetic acid levels were determined. L. reuteri LPB P01–001 behaves as an aciduric bacteria because it grows better in a low pH medium without pH control. However, the lactic acid production yield was practically half (9.22 g.L-1) of that obtained under a constant pH of 6.5, which reached 30.5 g.L-1 after 28 hours of fermentation. The acetic acid production was also higher under pH-controlled fermentation, reaching 10.09 g.L-1after 28 hours of fermentation. These parameters may raise the interest of those committed to the efficient production of a probiotic agent for swine.

Fermentation of seaweed sugars by Lactobacillus species and the potential of seaweed as a biomass feedstock

It is known that seaweeds differ greatly from land plants in their sugar composition. The current research on the L-lactic acid fermentation process focuses on land plant sugars as a carbon source, with the potential of seaweed sugars being largely ignored. This study examined the feasibility of seaweed biomass as a possible carbon source for the production of l-lactic acid, by comparing the fermentation of seaweed sugars (d-galactose, d-mannitol, l-rhamnose, d-glucuronic acid, and l-fucose) and land plant sugars (d-glucose, d-xylose, d-mannose, and l-arabinose). The experiments were repeated with 2 sugar acids (d-gluconic acid, d-glucaric acid) in order to investigate the effect of the degree of reduction of carbon source on the fermentation yield. This research also examined the effect of bacterial strain on the characteristics of fermentation reactions, by conducting l-lactic acid fermentation with 7 different Lactobacillus species. Taking into account the sugar composition of seaweed and the levels of lactic acid production from each pure sugar, it was possible to predict the lactic acid production yield of various seaweeds and land plants. From comparative analysis of the predicted lactic acid production yield, it was found that seaweeds are already comparable to lignocellulosics at the current stage of technology. If new technologies for the utilization of non-fermentable seaweed sugars are developed, seaweeds show promise as an even more useful biomass feedstock than lignocellulosics.

Lactic acid production from seaweed hydrolysate of Enteromorpha prolifera (Chlorophyta)

We examined the feasibility of using the green seaweed Enteromorpha prolifera as an alternative carbon source for chemical production. For this purpose, the chemical composition (proximate analysis, ultimate analysis, and mineral analysis) and acid hydrolysis of E. prolifera were investigated. In addition, lactic acid fermentation of E. prolifera hydrolysate was carried out using five Lactobacillus strains. The lactic acid yield, which is defined as the ratio of the lactic acid production to total sugar consumption, varied depending on the strains. Lactobacillus salivarius showed the highest lactic acid yield (68.5%), followed by Lactobacillus plantarum (66.0%), Lactobacillus rhamnosus (55.8%), Lactobacillus brevis (54.5%), and Lactobacillus casei (51.4%). The results shown in this study imply that E. prolifera would be competitive with lignocellulosic biomass such as corn stover in terms of lactic acid production yield and that green seaweed can be used as a feedstock for industrial production of chemicals.

Acid hydrolysis of sugarcane bagasse for lactic acid production

In order to use sugarcane bagasse as a substrate for lactic acid production, optimum conditions for acid hydrolysis of the bagasse were investigated. After lignin extraction, the conditions were varied in terms of hydrochloric (HCl) or sulfuric (H 2SO 4) concentration (0.5–5%, v/v), reaction time (1–5 h) and incubation temperature (90–120 °C). The maximum catalytic efficiency ( E) was 10.85 under the conditions of 0.5% of HCl at 100 °C for 5 h, which the main components (in g l −1) in the hydrolysate were glucose, 1.50; xylose, 22.59; arabinose, 1.29; acetic acid, 0.15 and furfural, 1.19. To increase yield of lactic acid production from the hydrolysate by Lactococcus lactis IO-1, the hydrolysate was detoxified through amberlite and supplemented with 7 g l −1 of xylose and 7 g l −1 of yeast extract. The main products (in g l −1) of the fermentation were lactic acid, 10.85; acetic acid, 7.87; formic acid, 6.04 and ethanol, 5.24.

Lactic acid fermentation on barley flour without additional nutrients

An amylolytic lactic acid producing Lactobacillus amylovorus produced 36 g/l of lactic acid in mixed cultures with L. casei without additional nutrients at 37 °C in 48 h, when barley flour concentration was 180 g/l (appr. 108 g/l starch) and barley malt quantity 0.8% of flour weight. This represented an improvement of up to 20% in comparison to the fermentation with L. amylovorus or L. casei alone. By simultaneous glucoamylase addition lactic acid production yield was about doubled. With L. casei the lactic acid yield was from 580 g in 72 h to 667 g in 144 h per kg barley flour.

Physiological restriction of the L‐lactic acid production by Rhizopus arrhizus

AbstractThe influence of basic physiological factors on the quality of inocula and L(+)‐lactic acid production by Rhizopus arrhizus CCM 81 09 were studied.The most effective preparation of the spores (5 × 107 spores/ml) and subsequent good lactate production was achieved on the agar medium with soil extract and malt agar. The optimum initial amount of active spores for inoculation was 103–104 spores/ml. The preparation of inoculum required intensive stirring with lower aeration and pH maintained in the range from 4.8 to 6.0 by the addition of CaCO3. The maximum yield of lactic acid production was achieved by using 5% (v/v) of 24‐h‐old inoculum. The intensity of lactic acid production in the inoculum was proportional to its production in the subsequent steps of fermentation and can be used as a fast control of the physiological state of the producers.

Optimization of the conditions of the fermentation of beet molasses to lactic acid by Lactobacillus delbrueckii

AbstractOptimization studies were carried out for the production of L‐lactic acid from the fermentation of beet molasses by Lactobacillus delbrueckii. A Central Composite Design was used to determine the optimum values of the process variables (temperature, pH, inoculum concentration, and initial sucrose concentration) for obtaining the maximum yield and the maximum volumetric productivity of lactic acid. Among the variables selected for study, it was found that all of them apart from the temperature significantly affected the responses (yield and volumetric productivity of lactic acid). The Central Composite Design also permitted formulating two second‐order polynomial empirical models relating to the responses and the significant variables. From these models it was possible to determine the value of the variables giving the maximum yield of lactic acid production (87.8%) and the maximum volumetric rate of lactic acid biosynthesis (2.7 g/l · h). Finally, the dependence of the lactic acid yield and productivity on the model variables was investigated. All conclusions are restricted to the experimental range studied.

Kinetics of lactic acid fermentation on glucose and corn by Lactobacillus amylophilus

AbstractThe biosynthesis of ammonium lactate, a product of lactic acid fermentation was studied from corn and glucose at five different pH values of 5.4 to 7.8. In the glucose fermentations, a 100% conversion of substrate was obtained resulting in a maximum lactic acid production yield of 93.2%. The optimum pH for the maximum volumetric rate of lactic acid biosynthesis (1.56 g dm−3 h−1) was between 6.0 and 6.5. The corn fermentations were slower than the glucose fermentations with a resulting lactic acid yield of 67.5%. Hydrolysis of corn by enzymatic or chemical methods as well as the use of ammonium hydroxide for pH control increased both the final concentration and the rates of lactic acid production. An enhanced yield of more than 90% was finally obtained in the corn fermentations. A logistic model adequately described the kinetics of biomass growth, lactic acid production and sugar utilization in the glucose fermentations at different pH values. The dynamics of lactic acid formation in the corn fermentations were also successfully described by the developed model. The dependence of the model parameters on pH was investigated.