Biotechnological Production Of Lactic Acid Research Articles

Response surface methodology optimisation enhancing lactic acid production from Prosopis africana pods by Rhizopus oryzae

Microbial fermentation of lignocellulosic biomass into lactic acid (LA) has received considerable attention because it ensures the valorisation of wastes and reduces dependence on fossil sources. First, the proximate and phytochemical compositions of Prosopis africana pods (PAP) were determined. Previous biologically-pretreated pods of Prosopis africana were then saccharified using dilute acid hydrolysis following a full factorial design. The factors optimized were acid type (HCl and H2SO4), acid concentration (1 %, 3 % and 5 %), solid loading ratio (5 %, 10 % and 20 %) and reaction time (15, 30 and 60 minutes). Several Rhizopus oryzae isolates were screened for LA production and the most prolific was molecularly identified. The factors affecting LA yield from PAP hydrolysate were screened using a half-factorial design. The significant factors were then optimised using Box-Behnken Design of Response Surface Methodology (RSM). The proximate analysis showed high levels of protein, lipid, ash and carbohydrates. The phytochemical analysis of PAP revealed the presence of flavonoids, alkaloids, saponins, phenols, tannins, glycosides and terpenoids. The hydrolysis conditions of 3 % HCl, 20 % solid loading and 15 minutes hydrolysis time yielded the highest reducing sugars of 42.5 g/L. The most promising isolate, identified as R. oryzae strain AK-22, produced 19.7 g/L after RSM optimization, a 38.1 % increase over yields from non-optimised conditions. These findings are on the biotechnological production of LA from the pods of Prosopis africana, an abundant yet under-utilised tree crop.

Potential of New Bacterial Strains for a Multiproduct Bioprocess Application: A Case Study Using Isolates of Lactic Acid Bacteria from Pineapple Silage of Costa Rican Agro-Industrial Residues

Lactic acid bacteria (LAB) with potential for the development of multi-product processes are necessary for the valorization of side streams obtained during the biotechnological production of lactic acid (LA). In this study, 14 LAB strains isolated from pineapple agro-industrial residues in Costa Rica were cultivated in microplates, and the six strains with the highest growth were selected for fermentation in microbioreactors to evaluate the production of LA and acetic acid, and the consumption of glucose. Lacticaseibacillus paracasei 6710 and L. paracasei 6714 presented the highest OD600 values (1.600 and 1.602, respectively); however, the highest LA (in g/L) production was observed in L. paracasei 6714 (14.50 ± 0.20) and 6712 (14.67 ± 0.42). L. paracasei 6714 was selected for bioreactor fermentation and reached a maximum OD600 of 6.3062 ± 0.141, with a LA yield of 84.9% and a productivity of 1.06 g L−1 h−1 after 21 h of fermentation. Finally, lipoteichoic acid (LTA) detection from biomass was performed and the antimicrobial activity of the compounds present in the supernatant was studied. LTA was detected from L. paracasei 6714 biomass, and its supernatant caused significant inhibition of foodborne surrogate microorganisms. LAB isolated from pineapple silage have biotechnological potential for multiproduct processes.

L-(+)-Lactic Acid from Reed: Comparing Various Resources for the Nutrient Provision of B. coagulans

Biotechnological production of lactic acid (LA) is based on the so-called first generation feedstocks, meaning sugars derived from food and feed crops such as corn, sugarcane and cassava. The aim of this study was to exploit the potential of a second generation resource: Common reed (Phragmites australis) is a powerfully reproducing sweet grass which grows in wetlands and creates vast monocultural populations. This lignocellulose biomass bears the possibility to be refined to value-added products, without competing with agro industrial land. Besides utilizing reed as a renewable and inexpensive substrate, low-cost nutritional supplementation was analyzed for the fermentation of thermophilic Bacillus coagulans. Various nutritional sources such as baker’s and brewer’s yeast, lucerne green juice and tryptone were investigated for the replacement of yeast extract. The structure of the lignocellulosic material was tackled by chemical treatment (1% NaOH) and enzymatic hydrolysis (Cellic® CTec2). B. coagulans DSM ID 14-300 was employed for the homofermentative conversion of the released hexose and pentose sugars to polymerizable L-(+)-LA of over 99.5% optical purity. The addition of autolyzed baker’s yeast led to the best results of fermentation, enabling an LA titer of 28.3 g L−1 and a yield of 91.6%.

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.

Use of wheat straw and chicken feather hydrolysates as a complete medium for lactic acid production

Biotechnological production of lactic acid has experienced a boom that is hindered only by the lack of low-cost, abundant material that might be used as a substrate for lactic acid bacteria. Such material should contain not only carbon but also complex nitrogen sources, amino acids and vitamins necessary for the balanced growth of the bacteria. Here, for the first time, a combination of hydrolysates of wheat straw and chicken feathers was used as a complete waste cultivation medium for lactic acid production. It was shown to be a promising substrate for lactic acid production, reducing the medium price by 73% compared with MRS broth, providing more than 98% lactic acid yield and high productivity (2.28 ± 0.68 g/l/h) in a fed-batch process using Lactobacillus reuterii LHR14.

Co-fermentation of the main sugar types from a beechwood organosolv hydrolysate by several strains of Bacillus coagulans results in effective lactic acid production

Bacillus coagulans is an interesting facultative anaerobic microorganism for biotechnological production of lactic acid that arouses interest. To determine the efficiency of biotechnological production of lactic acid from lignocellulosic feedstock hydrolysates, five Bacillus coagulans strains were grown in lignocellulose organosolv hydrolysate from ethanol/water-pulped beechwood. Parameter estimation based on a Monod-type model was used to derive the basic key parameters for a performance evaluation of the batch process. Three of the Bacillus coagulans strains, including DSM No. 2314, were able to produce lactate, primarily via uptake of glucose and xylose. Two other strains were identified as having the ability of utilizing cellobiose to a high degree, but they also had a lower affinity to xylose. The lactate yield concentration varied from 79.4 ± 2.1 g/L to 93.7 ± 1.4 g/L (85.4 ± 4.7 % of consumed carbohydrates) from the diluted organosolv hydrolysate.

Biotechnological Production of Organic Acids from Renewable Resources.

Biotechnological processes are promising alternatives to petrochemical routes for overcoming the challenges of resource depletion in the future in a sustainable way. The strategies of white biotechnology allow the utilization of inexpensive and renewable resources for the production of a broad range of bio-based compounds. Renewable resources, such as agricultural residues or residues from food production, are produced in large amounts have been shown to be promising carbon and/or nitrogen sources. This chapter focuses on the biotechnological production of lactic acid, acrylic acid, succinic acid, muconic acid, and lactobionic acid from renewable residues, these products being used as monomers for bio-based material and/or as food supplements. These five acids have high economic values and the potential to overcome the "valley of death" between laboratory/pilot scale and commercial/industrial scale. This chapter also provides an overview of the production strategies, including microbial strain development, used to convert renewable resources into value-added products.

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.

Bioutilisation of agro‐industrial waste for lactic acid production

SummaryWith the advancement in science and technology, the importance of bioconversion of industrial waste into value‐added products through biotechnological route has been realised. Moreover, to make the process economic and environment responsive, agro‐industrial waste/by‐products can be used as substrates in fermentation processes as an inexpensive raw material. In the field of food biotechnology, organic acids represent the third largest category among the biological products, which can be produced chemically or by fermentation process. Among organic acids, lactic acid holds an important position because of its multivariate applications in food, pharmaceutical, cosmetics, textiles and other industries. Traditionally, lactic acid was produced from pure substrates, but agricultural feedstocks and industrial by‐products have evoked the interest of researchers to use them as raw materials for the biotechnological production of lactic acid. The utilisation of biomass has gained major attention due to environmental hazards, scarcity of fossil fuels and meet the increasing world food and feed demand. Integrated biorefinery approaches have also been adopted for the production of lactic acid along with primary product to minimise the cost. This review provides comprehensive information on the recent advances in biotechnological production of lactic acid utilising agro‐industrial waste/by‐products.

Green metrics for sustainability of biobased lactic acid from starchy biomass vs chemical synthesis

The interest in the biotechnological production of lactic acid has increased due to the prospects of environmental friendliness and of using renewable resources instead of petrochemicals. Besides, this type of lactic acid is important for polylactic acid (PLA) production, as it is not toxic as packaging in food application while monomers of many fossil polymers are. However, lack of information can be found about the efficiency of fermentative production of lactic acid from biomass in compare with its production in a chemical way.The present paper reviews some of our recent studies concerning metrics relevant to the development of a cost-effective and sustainable viable processes for lactic acid production. In particular, the following metrics were taken for consideration: (i) material efficiency; (ii) total energy efficiency, (iii) economic added value and (iv) land use.Higher economical effect has been found by using biological conversion of wheat biomass to lactic acid vs chemical synthesis by increasing the energy efficiency by 47% and decreasing the total costs by 17%. Chemical synthesis from petrochemical resources always results in a racemic mixture of d/l-lactic acid, which is a major disadvantage of this approach, while fermentation-derived lactic acid mixtures of poly d(−) and poly l(+) give the high crystalline melting point (Tm), which is a very important criteria for improving PLA applicability for bioplastics production. Conversely, microbial lactic acid fermentation offers an advantage in terms of utilization of renewable carbohydrate biomass, low production temperature, low energy consumption, and the production of optically high pure lactic acid by selecting an appropriate strain.

Sugar beet syrups in lactic acid fermentation – Part I

Biotechnological production of lactic acid has been studied in various ways, e.g. microorganisms, fermentation processes, down-stream processes, fermentation substrates, and fermentation nutrients. The problems for all processes still are high costs for feedstock and fermentation nutrients. The objective of this study is a general evaluation of sugar beet thick juice from Pfeifer & Langen GmbH & Co. KG, Germany as a substrate for lactic acid production. In a series of fermentation experiments the results based on thick juice were comparable to those obtained using cane raw sugar and even better than using conventional corn starch as a fermentation subtrate. The most important findings for a later technical application are the high volumetric productivity (up to 5.5g·L–1·h–1), and the optical purity of the lactic acid (>99% ee l-LA).

Production of l-lactic acid by the yeast Candida sonorensis expressing heterologous bacterial and fungal lactate dehydrogenases

BackgroundPolylactic acid is a renewable raw material that is increasingly used in the manufacture of bioplastics, which offers a more sustainable alternative to materials derived from fossil resources. Both lactic acid bacteria and genetically engineered yeast have been implemented in commercial scale in biotechnological production of lactic acid. In the present work, genes encoding l-lactate dehydrogenase (LDH) of Lactobacillus helveticus, Bacillus megaterium and Rhizopus oryzae were expressed in a new host organism, the non-conventional yeast Candida sonorensis, with or without the competing ethanol fermentation pathway.ResultsEach LDH strain produced substantial amounts of lactate, but the properties of the heterologous LDH affected the distribution of carbon between lactate and by-products significantly, which was reflected in extra-and intracellular metabolite concentrations. Under neutralizing conditions C. sonorensis expressing L. helveticus LDH accumulated lactate up to 92 g/l at a yield of 0.94 g/g glucose, free of ethanol, in minimal medium containing 5 g/l dry cell weight. In rich medium with a final pH of 3.8, 49 g/l lactate was produced. The fermentation pathway was modified in some of the strains studied by deleting either one or both of the pyruvate decarboxylase encoding genes, PDC1 and PDC2. The deletion of both PDC genes together abolished ethanol production and did not result in significantly reduced growth characteristic to Saccharomyces cerevisiae deleted of PDC1 and PDC5.ConclusionsWe developed an organism without previous record of genetic engineering to produce L-lactic acid to a high concentration, introducing a novel host for the production of an industrially important metabolite, and opening the way for exploiting C. sonorensis in additional biotechnological applications. Comparison of metabolite production, growth, and enzyme activities in a representative set of transformed strains expressing different LDH genes in the presence and absence of a functional ethanol pathway, at neutral and low pH, generated a comprehensive picture of lactic acid production in this yeast. The findings are applicable in generation other lactic acid producing yeast, thus providing a significant contribution to the field of biotechnical production of lactic acid.

Bioconversion of ovine scotta into lactic acid with pure and mixed cultures of lactic acid bacteria

Scotta is the main by-product in the making of ricotta cheese. It is widely produced in southern Europe and particularly in Italy where it represents a serious environmental pollutant due to its high lactose content. With the aim of evaluating whether scotta bioconversion into lactic acid can be considered as an alternative to its disposal, besides providing it with an added value, here the growth, fermentative performances, and lactic acid productions of pure and mixed cultures of Lactobacillus casei, Lactobacillus helveticus, and Streptococcus thermophilus were evaluated on ovine scotta-based media, without and with the addition of nutritional supplements. The outcomes indicate that ovine scotta can be utilized for the biotechnological production of lactic acid with yields up to 92%, comparable to those obtained on cheese-whey. Indeed, the addition of nutritional supplements generally improves the fermentative performances of lactic acid bacteria leading to about 2 g l(-1) h(-1) of lactic acid. Moreover, the use of mixed cultures for scotta bioconversion reduces the need for nutritional supplements, with no detrimental effects on the productive parameters compared to pure cultures. Finally, by using L. casei and S. thermophilus in pure and mixed cultures, up to 99% optically pure L: -lactic acid can be obtained.

Comparison between Different Hydrolysis Processes of Vine-Trimming Waste to Obtain Hemicellulosic Sugars for Further Lactic Acid Conversion

Trimming vine shoot samples were treated with water under selected operational conditions (autohydrolysis reaction) to obtain a liquid phase containing hemicellulose-decomposition products. In a further acid-catalyzed step (posthydrolysis reaction), xylooligosaccharides were converted into single sugars for the biotechnological production of lactic acid using Lactobacillus pentosus. A wide range of temperatures, reaction times, and acid concentrations were tested during the autohydrolysis-posthydrolysis process to investigate their influence on hemicellulose solubilization and reaction products. The maximum concentration of hemicellulosic sugars was achieved using autohydrolysis at 210 degrees C followed by posthydrolysis with 1% H2SO4 during 2 h. Data from autohydrolysis-posthydrolysis were compared with the results obtained at the optima conditions assayed for prehydrolysis (3% H2SO4 at 130 degrees C during 15 min) based on previous works. Prehydrolysis extracted more hemicellulosic sugars from trimming vine shoots; however, the protein content in the hydrolysates from autohydrolysis-posthydrolysis was higher. The harsher conditions assayed during the autohydrolysis process and the higher content of protein after this treatment could induce Maillard reactions decreasing consequently the concentration of hemicellulosic sugars in the hydrolysates. Therefore, despite the several advantages of autohydrolysis (less equipment caused by the absence of mineral acid, less generation of neutralized sludges, and low cost of reagents) the poor results obtained in this work with no detoxified hydrolysates (Q P = 0.36 g/L h, Q S = 0.79 g/L h, Y P/S = 0.45 g/g, Y P/Sth = 61.5 %) or charcoal-treated hydrolysates (Q P = 0.76 g/L h, Q S = 1.47 g/L h, Y P/S = 0.52 g/g, Y P/Sth = 71.5 %) suggest that prehydrolysis of trimming vine shoots with diluted H2SO4 is more attractive than autohydrolysis-posthydrolysis for obtaining lactic acid through fermentation of hemicellulosic sugars with L. pentosus. Besides the higher hemicellulosic sugars concentration achieved when using the prehydrolysis technology, no detoxification steps are required to produce efficiently lactic acid (Q P = 1.14 g/L h; Q S = 1.64 g/L h; Y P/S = 0.70 g/g; Y P/Sth = 92.6 %), even when vinification lees are used as nutrients (Q P = 0.89 g/L h; Q S = 1.54 g/L h; Y P/S = 0.58 g/g; Y P/Sth = 76.1 %).

Biotechnological production of lactic acid integrated with fishmeal wastewater treatment by Rhizopus oryzae

Fishmeal wastewater, a seafood processing waste, was utilized for production of lactic acid and fungal biomass by Rhizopus oryzae AS 3.254 with the addition of sugars. The 30 g/l exogenous glucose in fishmeal wastewater was superior to starch in view of productivities of lactic acid and fungal biomass, and COD reduction. Fishmeal wastewater can be a replacement for peptone which was the most suitable nitrogen source for lactic acid production among the tested organic or inorganic nitrogen sources. Exogenous NaCl (12 g/l) completely inhibited the production of lactic acid and fungal growth. In the medium of COD 5,000 mg/l fishmeal wastewater with the addition of 30 g/l glucose, the maximum productivity of lactic acid was 0.723 g/l h corresponding to productivity of fungal biomass 0.0925 g/l h, COD reduction 84.9% and total nitrogen removal 50.3% at a fermentation time of 30 h.

Utilization of renewables for lactic acid fermentation

Originally, lactic acid was produced from pure substrates like glucose. Increasingly, however, agricultural feedstocks such as grains and green biomass are also being used as raw materials for the biotechnological production of lactic acid. A high-productivity lactic acid bacterium strain was selected, process parameters were optimized for the batch fermentation on a laboratory scale, and its performance at cultivation on a barley hydrolysate medium together with different supplements was examined. The present results for the cultivation of the Lactobacillus paracasei on complex nutrient broth are in the same range as those for another strain of the same species with pure glucose, de Man, Rogosa and Sharpe medium (MRS) minerals, peptone and yeast extract. Under these conditions, this strain was able to accumulate more than 100 g lactate/L in the MRS medium. Medium optimization experiments showed that the main part of the nitrogen-containing nutrients in the medium (peptone, yeast extract) can be replaced by protein extracts from green biomass (lucerne green juice). The green juice after pressing fresh biomass contains a series of nitrogen-containing compounds and inorganic salts, which are essential for cell growth. Thus, on laboratory scale, we have demonstrated that it is possible to substitute synthetic nutrients by renewable resources like cereals and green biomass without any loss of productivity. This high biomass concentration together with the number of living cells could increase the productivity to higher levels compared to the well-adapted synthetic nutrients of MRS.

Biotechnological production of lactic acid integrated with potato wastewater treatment by Rhizopus arrhizus

AbstractThis paper describes a feasibility study of a for lactic acid production integrated with are treatment of wastewater from an industrial starch plant. Rhizopus oryzae two strains, Rhizopus arrhizus and Rhizopus oligosporus were tested with respect to their capability to carry out simultaneous saccharification and fermentation to lactic acid using potato wastewater. Rhizopus arrhizus DAR 36017 was identified as a suitable strain that demonstrated a high capacity for starch saccharification and lactic acid synthesis. The optimal conditions, in terms of pH, temperature and starch concentration, for lactic acid production were determined. The selected fungal strain grew well in a pH range from 3.0 to 7.0. The addition of CaCO310 g dm−3 maintained the pH at 5.0–6.0 and significantly enhanced lactic acid production. Kinetic study revealed that almost complete starch saccharification and a lactic acid yield of 450g kg−1 could be achieved in 20 h and 28 h cultivation, respectively. The maximum lactic acid production 21 g dm−3 and mycelial biomass (1.7 g dm−3) were obtained at 30 °C. Besides the multiple bioproducts, total removal of suspended solids and 90% reduction of COD were achieved in a single no‐aseptic operation. Copyright © 2003 Society of Chemical Industry