Substrate For Lactic Acid Production Research Articles

Microbial conversion of agro-wastes for lactic acid production

Lactic acid (LA) is an organic compound produced via fermentation by microorganisms that can utilize a wide range of carbohydrate sources and has gained relevance in food industries for preservation, pharmaceutical industries as additives, textile industries as mordants and production of cosmetics and bioplastics. In spite of the various applications of lactic acid, its availability is a challenge, especially in developing countries like Nigeria and therefore has to be imported, making it very expensive. One of the core substrates for lactic acid production is glucose. This study focused on the production of lactic acid using reducing sugar from locally sourced agro-wastes (corncob, sugarcane bagasse, plantain peduncle and groundnut shell). Bacteria were isolated from the agro-wastes dumpsite and screened for lactic acid production using De Man Rogosa and Sharpe (MRS) agar. The agro-wastes were pretreated using NaOH and hydrolyzed using cellulase produced from Aspergillus niger. The lactic acid bacteria (LAB) were identified based on their cultural, morphological, biochemical and molecular characteristics. The screened isolates were used for the production of lactic acid in an MRS medium containing the agro-waste hydrolysates as the sole carbon source. The LAB isolate with the best ability for lactic acid production was ascertained using the spectrophotometric method. Eleven (11) isolates were obtained from the agro-wastes dumpsites. Lactiplantibacillus plantarum (accession number OM510300) from plantain peduncle dumpsites had the highest potential for lactic acid production (1.9558 g/L). The study revealed that Nigerian-locally sourced agro-wastes can be developed as an alternative source of reducing sugar for lactic acid production and thus leads to agro-wastes management in the environment.

Advanced Fermentation Techniques for Lactic Acid Production from Agricultural Waste

Lactic acid plays an important role in industrial applications ranging from the food industry to life sciences. The growing demand for lactic acid creates an urgent need to find economical and sustainable substrates for lactic acid production. Agricultural waste is rich in nutrients needed for microbial growth. Fermentative production of lactic acid from non-food-competing agricultural waste could reduce the cost of lactic acid production while addressing environmental concerns. This work provided an overview of lactic acid fermentation from different agricultural wastes. Although conventional fermentation approaches have been widely applied for decades, there are ongoing efforts toward enhanced lactic acid fermentation to meet the requirements of industrial productions and applications. In addition, agricultural waste contains a large proportion of pentose sugars. Most lactic-acid-producing microorganisms cannot utilize such reducing sugars. Therefore, advanced fermentation techniques are also discussed specifically for using agricultural waste feedstocks. This review provides valuable references and technical supports for the industrialization of lactic acid production from renewable materials.

Pivotal Role of Microbes in Solid Waste Management

LLactic acid bacteria (LAB) are used widely in food microbiology as probiotics and biopreservatives to extend shelf life of food items. Lactic acid produced by LAB strains are precursor of polylactic acid(PLA) that has growing demand as bioplastics that are biodegradable in nature replacing traditional plastics. LAB have the potential to utilize polysaccharides from various sources and produce lactic acid. The aim of this study is to identify lactic acid producing strains of lactic acid bacteria(LAB) that have efficiency in utilizing biodegradable fragment of domestic solid waste collected from residential areas of Coimbatore municipality for three days. The main objective of this study is to convert the biodegradable solid waste into lactic acid, a precursor of Poly lactic acid- PLA used as bioplastic. Important chemical parameters of the solid waste like phosphate estimation, nitrate estimation, Total organic carbon estimation were done following Indian standard analytical methods. Glucose consumption efficiency of Lacto bacillus sp.in solid waste substrate was analyzed in UV spectrometer at620nm by Anthrone method. Estimation of lactic acid produced was done in UV spectrometric analysis at 390nm using iron lactate formation. In this study, lactic acid bacteria were isolated from samples of milk, curd, idli batter and screened for lactic acid production. Three isolates were chosen for the study each one from milk, curd, idli batter and from biochemical tests and morphology confirmed as Lacto bacillus sp. Solid waste collected was pretreated with dilute acid heating and hydrolysate obtained was used as substrate for lactic acid production under optimized parameters. Three different substrates were chosen for lactic acid production and the results were compared. The three isolates of Lacto bacillus sp.were good producers of lactic acid and utilized biodegradable solid waste in an effective manner. 3-5 gm/lit of lactic acid was produced by the three strains of Lacto bacillus sp .Segregation of domestic solid waste collected, comprised of 40% biodegradable fragment, 40% nondegradable plastic, 20%miscellaneous waste. Lactic acid production from biodegradable portion is a preliminary step experimented in this study progressing in polylactic acid PLA pathway indirectly reducing plastic pollution. In a similar manner, nonbiodegradable plastic waste can be minimized using Exopolysaccharide pathway by Xanthomonas sp.that is reviewed in this study. Disposal of solid waste in an economical and greener way is a smart method of saving environment. Bioconversion of plastic into pseudoplastic xanthan gum by Xanthomonas sp.(through exopolysaccharide pathway) are greener techniques to crush down the accumulated plastic mountains to ground level.

Saccharina latissima, candy-factory waste, and digestate from full-scale biogas plant as alternative carbohydrate and nutrient sources for lactic acid production

To substitute petroleum-based materials with bio-based alternatives, microbial fermentation combined with inexpensive biomass is suggested. In this study Saccharina latissima hydrolysate, candy-factory waste, and digestate from full-scale biogas plant were explored as substrates for lactic acid production. The lactic acid bacteria Enterococcus faecium, Lactobacillus plantarum, and Pediococcus pentosaceus were tested as starter cultures. Sugars released from seaweed hydrolysate and candy-waste were successfully utilized by the studied bacterial strains. Additionally, seaweed hydrolysate and digestate served as nutrient supplements supporting microbial fermentation. According to the highest achieved relative lactic acid production, a scaled-up co-fermentation of candy-waste and digestate was performed. Lactic acid reached a concentration of 65.65 g/L, with 61.69% relative lactic acid production, and 1.37 g/L/hour productivity. The findings indicate that lactic acid can be successfully produced from low-cost industrial residues.

Enhanced lactic acid production with indigenous microbiota from date pulp waste and keratin protein hydrolysate from chicken feather waste

A substantial amount of keratin, a key protein with excellent material-forming properties, can be sustainably extracted from chicken feathers, which are commonly discarded in the poultry industry. The keratin protein found in chicken feathers can serve as a nitrogen source and a pH regulator for microbes. In this study, the use of indigenous bacteria and extracted keratin protein hydrolysate from chicken feathers as a nitrogen source improved lactic acid production from date pulp waste by fermentation. After six days of optimal dark fermentation time at pH 6, the maximum concentration of L-lactic acid (46.2 g/L) was obtained with keratin protein hydrolysate and date pulp waste substrate. Under the same conditions, the value was 2.12 times higher than that of the date pulp waste substrate (21.7 g/L) without the addition of keratin protein hydrolysate. Under optimal conditions, volumetric lactic acid productivity and yield were 7.7 g/L/day and 0.3 g/g substrate, respectively. Keratin protein hydrolysate proved to be the most effective neutralizing agent for L-lactic acid production at a concentration of 6 g/L. The combination of keratin protein hydrolysate and date pulp waste was studied for the first time as a substrate for lactic acid production. Keratin protein hydrolysate was found to buffer pH changes during fermentation. Poultry and plant by-products are usually available in agriculturally challenged areas. Therefore, this study provides an excellent opportunity to recycle waste and improve the overall circular economy of such agro-industrial complexes.

Use of Corn-Steep Water Effluent as a Promising Substrate for Lactic Acid Production by Enterococcus faecium Strain WH51-1

Various challenges facing the industrial production of bio-based lactic acid (LA) such as cost of raw materials and nitrogen sources, as well as contamination risk by mesophilic and neutrophilic producers, should be overcome for the commercial production. This study aimed to investigate the feasibility of corn steep water (CSW) as a raw material for LA production using a newly thermo-alkali-tolerant lactic acid bacterium. The physicochemical characteristics of CSW were investigated. The high carbohydrates, proteins, amino acids, vitamins, essential elements, minerals, and non-protein nitrogenous compounds content confirmed that the CSW is a promising substrate for LA production. Out of 67 bacterial isolates, Enterococcus faecium WH51-1 was selected based on its tolerance to high temperatures and inhibitory compounds (sodium metabisulfate, sodium chloride, sodium acetate, and formic acid). Fermentation factors including sugar concentration, temperature, inoculum size, and neutralizing agents were optimized for LA production. Lactic acid concentration of about 44.6 g/L with a high yield (0.89 ± 0.02 g/g) was obtained using 60 g/L of CSW sugar, inoculum size 10% (v/v), 45 °C, and sodium hydroxide or calcium carbonate as a neutralizing agent. These results demonstrated the potential of strain WH51-1 for LA production using CSW effluent as raw material.

Effect of honeycomb, granular, and powder activated carbon additives on continuous lactic acid fermentation of complex food waste with mixed inoculation

To accelerate and stabilize lactic acid fermentation from food waste, three types of activated carbon, including honeycomb activated carbon, granular activated carbon, and powder activated carbon, were tested as additives in continuous food waste fermentation processes. The results showed that carbohydrate was the primary substrate for lactic acid production, but its conversion reached a high, stable level after a long period of microbial acclimation in the control system. Activated carbon, especially honeycomb activated carbon accelerated the stabilization of lactic acid fermentation and enhanced the tolerance of fermentation systems to a hostile and fluctuating environment. The addition of activated carbon increased the oxidation-reduction potential to approximately 100mV and altered the microbial communities. Homolactic fermentation bacteria were dominant in all the systems, and the honeycomb activated carbon addition stimulated the growth of unclassified Lactobacillus and immobilized Lactobacillus panis with strong carbohydrate metabolism. In addition, powder activated carbon enhanced the degradation of protein due to the multiplying Pseudomonas. At the stable stage, the organic conversion rates were close in the control system and the systems with the activated carbon addition, and the lactic acid concentrations in these systems remained at 8000-10,000mg/L. Considering the cost of the additives, honeycomb activated carbon is a good choice to stabilize lactic acid production from food waste.

Potential of macroalgae-based biorefinery for lactic acid production from exergy aspect

The increasing production of plastics has raised concerns over the depletion of fossil fuels. In addition, the environmental issues associated with the improper management of plastic waste are increasingly alarming. Therefore, there is a sharp rise of researches conducted on one of the most promising biopolymers for the production of biodegradable plastics, which is known as polylactic acid (PLA). Subsequently, this has led to an increased interest in the production of its monomer, lactic acid (LA). However, the high production cost of LA has been limiting its large-scale manufacturing. The utilization of expensive raw materials and complicated downstream processes have led to the high overall production cost of LA. This review explores the potential of 3G feedstock, specifically macroalgae biomass, as a substrate for LA production. Then, the recent technological advancements for LA production and the challenges currently faced in the LA industry are addressed. Lastly, the sustainability aspect of macroalgae biomass is evaluated economically and environmentally by utilizing engineering tools such as life cycle assessment and exergy analysis, which represent the highlights of this review paper.

Municipal biopulp as substrate for lactic acid production focusing on downstream processing

A primary target in lactic acid production is to reduce the production cost. Due to its high content of fermentable carbohydrates and low-cost, municipal biopulp can represent a promising feedstock to match this target. In addition to low-cost raw materials, a cost-effective downstream separation process (DSP) for the recovery of lactic acid is necessary to improve the overall competitiveness of the process. In the present study, lactic acid was produced from municipal biopulp obtaining a yield and titer of 82.6 ± 2.3%. g/g of total sugars and 16.1 ± 0.4 g/L, respectively. Two downstream processes (DSP1 and DSP2) were also investigated to recover lactic acid from the fermentation broth. DSP1 consisted of a pre-purification step (centrifugation, ultrafiltration, and activated carbon) followed by ion-exchange and vacuum distillation. DSP1 resulted in a recovery of 75.70 ± 1.5% and lactic acid purity of 72.50 ± 2.0%. In the DSP2, a nanofiltration unit was included after the pre-purification step, which resulted in a higher lactic acid purity of 82.0 ± 1.5% but compromising the recovery, i.e. 65.0 ± 1.5%. Overall, the results of the present study indicate the feasibility to use municipal biopulp as a low-cost feedstock for lactic acid production, and thus efforts should be focused to optimize the fermentation and DSP2 steps.

Trends and hassles in the microbial production of lactic acid from lignocellulosic biomass

Lactic acid is an important biomolecule extensively used in various industries for the production of foods, drugs, cosmetics, bioplastic polylactic acid (PLA), etc. Microbial fermentation has proven to be an auspicious approach for lactic acid industrial production because it allows for the utilization of renewable green energy sources. Different biotechnological techniques have been explored to increase lactic acid production. However, this bio-based production route suffers from the major shortcoming derived from the limited availability of fermentable starchy substrates. This concern has led to the search for cost-effective and widely available alternative substrates. Lignocellulosic biomass, due to its abundance and continuous production, is presented as a viable substitute substrate for lactic acid production. However, various challenges stemming from the complexity of polymeric sugars are linked with the use of lignocellulosic materials. The potential solutions to maximize the benefits of using lignocellulosic biomass in LA production should be considered. This review examined and discussed recent progress in the production of lactic acid using lignocellulosic biomass and highlights potential strategies for improving its production. Additionally, the most recent purification techniques are summarized. Building upon this knowledge will set the stage for the further establishment of innovative sustainability approaches to circular bio-economy. • This study explores the potential of using lignocellulosic biomass (LCB) in lactic acid (LA) production. • The efficiency of lactic acid fermentation depends on LCB pretreatment and enzymatic hydrolysis. • Novel green methods for pre-treatment of LCB for LA fermentation have been highlighted. • Trends and hassles in LA fermentation using LCB have been discussed. • Purification techniques and applications of LA in diverse fields have been also reviewed.

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.

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.

Utilization of Cashew Apple Juice as a Substrate for Lactic Acid Production

Utilization of Cashew Apple Juice as a Substrate for Lactic Acid Production

Screening of media components and process parameters for production of L(+) lactic acid from potato waste liquid using amylolytic Rhizopus oryzae

The utilization of potato waste liquid instead of synthetic substrates for lactic acid production cannot only reduce the production cost but also makes the process environment effective. Unlike many lactic acid bacteria, lactic acid producing Rhizopus strains generates L(+) lactic acid as a sole isomer of lactic acid. Furthermore, some Rhizopus spp. are amylolytic in nature and can produce lactic acid from starchy substrates without prior saccharification. This study aimed at the utilization of potato waste liquid for the production of L(+) lactic acid using amylolytic Rhizopus oryzae MTCC 8784. The effect of media components and process parameters on simultaneous saccharification and fermentation of potato waste liquid by fungal strain has been studied to maximize the production of L(+) lactic acid. The results revealed that highest lactic acid production (15.5 g l–1) was obtained with potato waste liquid containing 30 g l–1 starch supplemented with soya okara hydrolysate (1.5%, v/v), calcium carbonate (1.5%, w/v), and salts. In terms of process parameters, the maximum L(+) lactic acid (18.15 g l–1) production was obtained at pH 6 with temperature 30 °C, agitation of 150 r.p.m., after incubation period of 48 h.

Effect of fermentation conditions on L-lactic acid production from soybean straw hydrolysate.

Four types of straw, namely, soybean, wheat, corn, and rice, were investigated for use in lactic acid production. These straws were mainly composed of cellulose, hemicellulose, and lignin. After pretreatment with ammonia, the cellulose content increased, whereas the hemicellulose and lignin contents decreased. Analytical results also showed that the liquid enzymatic hydrolysates were primarily composed of glucose, xylose, and cellobiose. Preliminary experiments showed that a higher lactic acid concentration could be obtained from the wheat and soybean straw. However, soybean straw was chosen as the substrate for lactic acid production owing to its high protein content. The maximum lactic acid yield (0.8 g/g) and lactic acid productivity (0.61 g/(l/h)) were obtained with an initial reducing sugar concentration of 35 g/l at 30°C when using Lactobacillus casei (10% inoculum) for a 42 h fermentation period. Thus, the experimental results demonstrated the feasibility of using a soybean straw enzymatic hydrolysate as a substrate for lactic acid production.

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).

Distillery Stillage as a New Substrate for Lactic Acid Production in Batch and Fed-batch Fermentation

Please cite this article as: Djukic-Vukovic A., Mojovic L., Nikolic S., Pejin J., Kocic-Tanackov S., Mihajlovski K., 2013, Distillery stillage as a new substrate for lactic acid production in batch and fed-batch fermentation, Chemical Engineering Transactions, 34, 97-102 DOI:10.3303/CET1334017 97 Distillery Stillage as a New Substrate for Lactic Acid Production in Batch and Fed-batch Fermentation Aleksandra Djukic-Vukovic *, Ljiljana Mojovic, Svetlana Nikolic, Jelena Pejin, Suncica Kocic-Tanackov, Katarina Mihajlovski Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia adjukic@tmf.bg.ac.rs

Optimization of Sulfide/Sulfite Pretreatment of Lignocellulosic Biomass for Lactic Acid Production

Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na2S and Na2SO3, which had high coefficient of determination (R 2) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na2S and Na2SO3 remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na2S at 130°C for 2.3–3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na2SO3 showed higher hydrolysis yield (86.34%) as compared to Na2S while other biomass substrates showed 2.0–3.0% less yield with Na2SO3. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL−1 of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively.

Production of Lactic Acid from Kenaf Core Hydrolysate by<i> Rhizopus oryzae</i> FTCC 5215

Lactic acid (LA) is commercially produced biologically using food-derived raw materials such as potato and corn. It seems to be less economical since they have to compete with the food sources industries. Thus, kenaf (Hibiscus cannabinus) is found to be the best alternative to substitute the raw material for LA production. In this paper, kenaf core were used as the substrate for production of LA by Rhizopus oryzae FTCC 5215. Since kenaf is one type of lignocellulosic material which is naturally resistant to breakdown to its structural sugars, it will inhibit microorganisms to be accessed through. Thus, hydrolysis process is needed as the aid for the liberation glucose. The highest value of lactic acid produced is 15.2 g/L at 25 oC with speed 200 rpm.

THE EFFECT OF DELIGNIFICATION PROCESS WITH ALKALINE PEROXIDE ON LACTIC ACID PRODUCTION FROM FURFURAL RESIDUES

Furfural residues produced from the furfural industry were investigated as a substrate for lactic acid production by simultaneous saccharification and fermentation (SSF). Alkaline peroxide was used for delignification of furfural residues to improve the final lactic acid concentration. The residue was treated with 1.3% to 1.7% hydrogen peroxide at 80 °C for 1 h with a substrate concentration of 3.33%. SSF of furfural residues with different delignification degrees were carried out to evaluate the effect of delignification degree on lactic acid production. Using corn hydrolysates/ furfural residues as substrates, SSF with different media were carried out to investigate the effect of lignin on the interaction between enzymes and lactic acid bacteria. Lactic acid bacteria had a negative effect on cellulase, thus resulting in the reduction of enzyme activity. Lignin and nutrients slowed down the decreasing trend of enzyme activity. A higher delignification resulted in a slower fermentation rate and lower yield due to degradation products of lignin and the effect of lignin on the interaction between enzymes and lactic acid bacteria. For the purpose of lactic acid production, a moderate delignification (furfural residues with the lignin content of 14.8%) was optimum.