Fermentative Production Of Lactic Acid Research Articles

Simultaneous Saccharification and Fermentation of Sugar Beet Pulp with Mixed Bacterial Cultures for Lactic Acid and Propylene Glycol Production.

Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles. Lactic acid is one of the primary platform chemicals, and can be used to synthesize a wide variety of useful products, including green propylene glycol. A series of controlled batch fermentations was conducted under various conditions, including pretreatment with enzymatic hydrolysis. Inoculation was performed in two sequential stages, to avoid carbon catabolite repression. Biologically-synthesized lactic acid was catalytically reduced to propylene glycol over 5% Ru/C. The highest lactic acid yield was obtained with mixed cultures. The yield of propylene glycol from the biological lactic acid was similar to that obtained with a water solution of pure lactic acid. Our results show that simultaneous saccharification and fermentation enables generation of lactic acid, suitable for further chemical transformations, from agricultural residues.

Extracellular protease derived from lactic acid bacteria stimulates the fermentative lactic acid production from the by-products of rice as a biomass refinery function

A lactic acid producing bacterium, Lactobacillus rhamnosus M-23, newly isolated from a rice washing drainage storage tank was found to produce l-(+)-lactic acid from a non-sterilized mixture of rice washing drainage and rice bran without any additions of nutrients under the simultaneous saccharification and fermentation (SSF) process. This strain has the ability to utilize the non-sterilized rice washing drainage and rice bran as a source of carbohydrate, saccharifying enzymes and nutrients for lactic acid production. Observation of extracellular protease activity in SSF culture broth showed that a higher protease activity was present in strain M-23 than in other isolated lactic acid producing bacteria (LABs). To investigate the structural changes of solid particles of rice washing drainage throughout LAB cultivation, scanning electron microscopic (SEM) observation and Fourier transform infrared-spectroscopy (FT-IR) analysis were performed. The results of the SEM observation showed that the surface material could be removed from solid particles of rice washing drainage treated by culture broth (supernatant) of strain M-23, thus exposing the crystal structure of the starch particle surface. The results of the FT-IR analysis revealed that the specific transmittance decrease of the CC and CO stretching and OH group of the solid particles of the rice washing drainage were highly correlated with the produced lactic acid concentration and extracellular protease activity, respectively. These results demonstrate the high lactic acid producing ability of strain M-23 from a non-sterilized mixture of rice washing drainage and rice bran under the SSF condition due to the removal of proteinaceous material and exposure of the starch particle surface by extracellular protease.

Novel homologous lactate transporter improves l-lactic acid production from glycerol in recombinant strains of Pichia pastoris

BackgroundCrude glycerol is the main byproduct of the biodiesel industry. Although it can have different applications, its purification is costly. Therefore, in this study a biotechnological route has been proposed for further utilization of crude glycerol in the fermentative production of lactic acid. This acid is largely utilized in food, pharmaceutical, textile, and chemical industries, making it the hydroxycarboxylic acid with the highest market potential worldwide. Currently, industrial production of lactic acid is done mainly using sugar as the substrate. Thus here, for the first time, Pichia pastoris has been engineered for heterologous l-lactic acid production using glycerol as a single carbon source. For that, the Bos taurus lactate dehydrogenase gene was introduced into P. pastoris. Moreover, a heterologous and a novel homologous lactate transporter have been evaluated for l-lactic acid production.ResultsBatch fermentation of the P. pastoris X-33 strain producing LDHb allowed for lactic acid production in this yeast. Although P. pastoris is known for its respiratory metabolism, batch fermentations were performed with different oxygenation levels, indicating that lower oxygen availability increased lactic acid production by 20 %, pushing the yeast towards a fermentative metabolism. Furthermore, a newly putative lactate transporter from P. pastoris named PAS has been identified by search similarity with the lactate transporter from Saccharomyces cerevisiae Jen1p. Both heterologous and homologous transporters, Jen1p and PAS, were evaluated in one strain already containing LDH activity. Fed-batch experiments of P. pastoris strains carrying the lactate transporter were performed with the batch phase at aerobic conditions followed by an aerobic oxygen-limited phase where production of lactic acid was favored. The results showed that the strain containing PAS presented the highest lactic acid titer, reaching a yield of approximately 0.7 g/g.ConclusionsWe showed that P. pastoris has a great potential as a fermentative organism for producing l-lactic acid using glycerol as the carbon source at limited oxygenation conditions (below 0.05 % DO in the bioreactor). The best strain had both the LDHb and the homologous lactate transporter encoding genes expressed, and reached a titer 1.5 times higher than the strain with the S. cerevisiae transporter. Finally, it was also shown that increased lactic acid production was concomitant to reduction of acetic acid formation by half.

Fermentative lactic acid production from coffee pulp hydrolysate using Bacillus coagulans at laboratory and pilot scales

In this study, the lignocellulosic residue coffee pulp was used as carbon source in fermentative l(+)-lactic acid production using Bacillus coagulans. After thermo-chemical treatment at 121°C for 30min in presence of 0.18molL−1 H2SO4 and following an enzymatic digestion using Accellerase 1500 carbon-rich hydrolysates were obtained. Two different coffee pulp materials with comparable biomass composition were used, but sugar concentrations in hydrolysates showed variations. The primary sugars were (gL−1) glucose (20–30), xylose (15–25), sucrose (5–11) and arabinose (0.7–10). Fermentations were carried out at laboratory (2L) and pilot (50L) scales in presence of 10gL−1 yeast extract. At pilot scale carbon utilization and lactic acid yield per gram of sugar consumed were 94.65% and 0.78gg−1, respectively. The productivity was 4.02gL−1h−1. Downstream processing resulted in a pure formulation containing 937gL−1l(+)-lactic acid with an optical purity of 99.7%.

Application of acid tolerant Pedioccocus strains for increasing the sustainability of lactic acid production from cheese whey

The major challenge within the presented study is the possibility to increase the effectiveness of fermentative lactic acid production. Four acid tolerant Pedioccocus spp. strains, previously isolated from sourdough medium, were screened for their ability to produce the enantioselective lactic acid (LA) from cheese whey and compared to the traditional in dairy technology Lactobacillus delbrüeckii spp. bulgaricus. The effects of lactose hydrolysis by using commercial β-galactosidase from Aspergillus oryzae and acid neutralization on fermentation performance and LA stereoisomer ratio were investigated. The Pediococcus pentosaceus strains were indicated as the DL-forming lactic acid bacteria, in which the percentage of the l(+)-lactic acid is high (75% from the total LA), while Pediococcus acidilactici and Lactobacillus bulgaricus produced L(+) and D(−) lactic acid, respectively. The L/D ratio could be increased by using enzyme hydrolysed whey for fermentation; however, prolonged fermentation induced the formation of d(−)-lactic acid. Experiment revealed the different tolerance of tested LAB to acid medium, thus required the different amounts of neutralizing agent. The maximum production of l(+)-lactic acid up to 47.0–51.2 g/L from hydrolysed whey was acquired in a pH 4.4–4.5 by P. acidilactici KTU05-7 and P. pentosaceus KTU05-9 using 2% (w/v) of CaCO3, while the use of L. bulgaricus required a threefold higher amount of the neutralizing agent.

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.

Production, optimization and characterization of lactic acid by Lactobacillus delbrueckii NCIM 2025 from utilizing agro-industrial byproduct (cane molasses).

In the present work Lactobacillus delbrueckii was used to utilize agro-industrial byproduct (cane molasses) for lactic acid production under submerged fermentation process. Screening of LAB was done by Fourier transform infra red spectroscopy (FTIR). Effect of different amino acids (DL-Phenylalanine, L-Lysine and DL-Aspartic acid) on the fermentation process was done by high performance liquid chromatography (HPLC). Central composite rotatable design (CCRD) was used to optimize the levels of three parameters viz. tween 80, amino acid and cane molasses concentration during fermentative production of lactic acid. Under optimum condition lactic acid production was enhanced from 55.89g/L to 84.50g/L. Further, validation showed 81.50g/L lactic acid production. Scale up was done on 7.5L fermentor. Productivity was found to be 3.40g/L/h which was higher than previous studies with reduced fermentation time from 24h to 12h. Further characterization of lactic acid was done by FTIR.

Optimization of Nutrients in Fermentative Lactic Acid Production Using Oil Palm Trunk Juice as Substrate

Complex nutrients e.g. carbon, nitrogen, peptides, vitamin and salts significantly play important roles in lactic acid production efficiency depending on types of microorganism and sources of raw material. In this study oil palm trunk juice and Lactobacillus rhamnosus TISTR 108 (ATTC 10863) were utilized for lactic acid production. Additional nutrients including peptone, yeast extract and mixed salts were tested. Response surface methodology involving Box Behkhen Design (BBD) was applied to examine the optimal condition. Prediction of optimization was performed using full quadratic regression equation. The predicted maximum lactic acid concentration was obtained at 64.05 g·l-1 within a period of 48 h under an optimal condition of 10 g·l-1 peptone with mixed salts containing 0.4 g·l-1 MgSO4·7H2O, 0.1 g·l-1 MnSO4·4H2O, 3 g·l-1 K2HPO4, 3 g·l-1 KH2PO4 and 3 g·l-1 CH3COONa·3H2O in 250 ml shake flask using CaCO3 as a titrant. Verification of optimization condition was performed in 2 l fermenter using Ca(OH)2 as neutralizing agent. Increase in lactic acid fermentation was achieved at 92.81 g·l-1 at 48 h cultivation. The lactic acid yield and volumetric productivity were 0.94 g·g-1 and 1.91 g l-1·h-1, respectively. This suggests that OPT juice is potentially used as carbon and nutrient sources for lactic acid production.

Biowaste: A Lactobacillus habitat and lactic acid fermentation substrate

Composite organic waste was assessed for its physical, chemical and microbial suitability to serve as a substrate for the fermentative production of lactic acid. The biowaste studied was highly acidic (pH 4.3) and had high organic carbon content (45%). A clone library identified 90% of the bacterial community were lactic acid bacteria, mainly represented by Lactobacilli (70%). Cultivation using semiselective media identified Lactobacillus plantarum, Lactobacillus brevis and their closest relatives as the dominating taxa. PCR-DGGE using general bacterial and lactic acid bacterial specific primers resulted in little heterogeneity of microbial community. These data indicate that biowaste is a preferred habitat of lactic acid bacteria, suggesting that the unsterilized biowaste and its natural flora could be used in a fermentation process for lactic acid production. Such kind of biowaste application could be an alternative for current substrates and provide a modern, efficient and environmental friendly waste treatment technology.

Fermentative lactic acid production from a renewable carbon source under response surface optimized conditions without alkali addition: a membrane-based green approach

Experimental investigations were carried out on production of lactic acid from sugar cane juice by Lactobacillus delbruckii in a membrane-integrated and non-neutralizing fermentation system after an initial optimization study. As the process produced lactic acid directly instead of through lactate salt as in traditional processes, many intermediate steps could be bypassed. Most relevant operating parameters like temperature, concentrations of yeast extract, and peptone were optimized first through rigorous experimentation following response surface methodology. At 41°C, 116.28 g l−1 lactic acid concentrations was reached with 13.82 g l−1 yeast extract and 7.69 g l−1 peptone concentration. However, higher yield (96%) was obtained with diluted sugarcane juice containing 102.20 g l−1 sucrose. The most remarkable achievement of this new design is that it can produce lactic acid with high degree of purification directly from a renewable and cheap carbon source in an eco-friendly process representing high process intensification.

New trends and challenges in lactic acid production on renewable biomass

Lactic acid is a relatively cheap chemical with a wide range of applications: as a preservative and acidifying agent in food and dairy industry, a monomer for biodegradable poly-lactide polymers (PLA) in pharmaceutical industry, precursor and chemical feedstock for chemical, textile and leather industries. Traditional raw materials for fermentative production of lactic acid, refined sugars, are now being replaced with starch from corn, rice and other crops for industrial production, with a tendency for utilization of agro industrial wastes. Processes based on renewable waste sources have ecological (zero CO2 emission, eco-friendly by-products) and economical (cheap raw materials, reduction of storage costs) advantages. An intensive research interest has been recently devoted to develop and improve the lactic acid production on more complex industrial by-products, like thin stillage from bioethanol production, corncobs, paper waste, straw etc. Complex and variable chemical composition and purity of these raw materials and high nutritional requirements of Lare the main obstacles in these production processes. Media supplementation to improve the fermentation is an important factor, especially from an economic point of view. Today, a particular challenge is to increase the productivity of lactic acid production on complex renewable biomass. Several strategies are currently being explored for this purpose such as process integration, use of Lwith amylolytic activity, employment of mixed cultures of Land/or utilization of genetically engineered microorganisms. Modern techniques of genetic engineering enable construction of microorganisms with desired characteristics and implementation of single step processes without or with minimal pre-treatment. In addition, new bioreactor constructions (such as membrane bioreactors), utilization of immobilized systems are also being explored. Electrodialysis, bipolar membrane separation process, enhanced filtration techniques etc. can provide some progress in purification technologies, although it is still remaining the most expensive phase in the lactic acid production. A new approach of parallel production of lactic bacteria biomass with probiotic activity and lactic acid could provide additional benefit and profit rise in the production process.

Metabolic engineering of Escherichia coli for the production of polylactic acid and its copolymers

Polylactic acid (PLA) is a promising biomass-derived polymer, but is currently synthesized by a two-step process: fermentative production of lactic acid followed by chemical polymerization. Here we report production of PLA homopolymer and its copolymer, poly(3-hydroxybutyrate-co-lactate), P(3HB-co-LA), by direct fermentation of metabolically engineered Escherichia coli. As shown in an accompanying paper, introduction of the heterologous metabolic pathways involving engineered propionate CoA-transferase and polyhydroxyalkanoate (PHA) synthase for the efficient generation of lactyl-CoA and incorporation of lactyl-CoA into the polymer, respectively, allowed synthesis of PLA and P(3HB-co-LA) in E. coli, but at relatively low efficiency. In this study, the metabolic pathways of E. coli were further engineered by knocking out the ackA, ppc, and adhE genes and by replacing the promoters of the ldhA and acs genes with the trc promoter based on in silico genome-scale metabolic flux analysis in addition to rational approach. Using this engineered strain, PLA homopolymer could be produced up to 11 wt% from glucose. Also, P(3HB-co-LA) copolymers containing 55-86 mol% lactate could be produced up to 56 wt% from glucose and 3HB. P(3HB-co-LA) copolymers containing up to 70 mol% lactate could be produced to 46 wt% from glucose alone by introducing the Cupriavidus necator beta-ketothiolase and acetoacetyl-CoA reductase genes. Thus, the strategy of combined metabolic engineering and enzyme engineering allowed efficient bio-based one-step production of PLA and its copolymers. This strategy should be generally useful for developing other engineered organisms capable of producing various unnatural polymers by direct fermentation from renewable resources.

Analysis of a functional lactate permease in the fungus Rhizopus

The fungus Rhizopus is frequently used for fermentative production of lactic acid, but little is known about the mechanisms or proteins for transporting this carboxylic acid. Since transport of the lactate anion across the plasma membrane is critical to prevent acidification of the cytoplasm, we evaluated the functionality of two lactate-proton symport paralogs, LacA and LacB, from Rhizopus delemar. Both of these proteins showed significant ancestral homology to bacterial lactate permease with 46–50% identity to similar homologs from the genus Burkholderia. Based on qPCR, the highest level of expression in Rhizopus for the lacA gene was on complex medium containing pyruvate, while lacB transcript was barely detected with all of the tested culture conditions. A Saccharomyces cerevisiae jen1 deletion strain lacking the ability to transport monocarboxylates was restored for growth on lactate and pyruvate with the expression of LacA. Expression of the LacB in this same strain did not confer the ability to grow on either carbon source. LacA expression also allowed active transport of L-[ 14C(U)]-lactate into yeast cells and this accumulation was inhibited by the proton uncoupler carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone. Translation fusions with GFP showed that LacA accumulates primarily in the plasma and vacuolar membrane, while LacB is dispersed throughout the cytoplasm. These results indicate that the Rhizopus LacA is a functional lactate symport that is probably involved in uptake of pyruvate or lactate, while the physiological role of LacB is unknown.

Fermentative lactic acid production with a metabolically engineered yeast immobilized in photo-crosslinkable resins

In this study, the immobilization technique involving photo-crosslinkable resin gels was used for lactic acid production. Saccharomyces cerevisiae OC-2T T165R , a metabolically engineered yeast that produces optically pure l(+)-lactic acid, was immobilized in hydrophilic photo-crosslinked resin gels as a biocatalyst. Three resin gels, TEP 1, TEP 2 and TEP 3, were examined and all of them showed high performance as to lactic acid production. Resin gel TEP 1, which exhibited the highest productivity among the resin gels was used for 15 consecutive batch fermentations without decreases in productivity and mechanical deformation, indicating that it was a suitable carrier for long-term lactic acid fermentation. Moreover, the use of the immobilization technique can improve the productivity of the metabolically engineered yeast in the fermentation with or without extraction, showing promise for using the immobilized engineered yeast for lactic acid production.

Lactic acid production from recycled paper sludge by simultaneous saccharification and fermentation

Concentrated sludge generated in large amounts by the wastewater treatment facilities of recycling paper plants raises a serious disposal problem requiring urgent solution. This recycled paper sludge (RPS) is an industrial waste with high polysaccharide content. As previously demonstrated, cellulosic and hemicellulosic fractions of RPS can be completely converted by enzymatic hydrolysis (using Celluclast ®1.5 L with Novozym ®188) into the constitutive glucose and xylose. These monosaccharides can be used on fermentation media to obtain a variety of products, such as lactic acid, which has an expanding market as precursor of biodegradable polylactides. Hence the purpose of the present work is to evaluate the performance of RPS as feedstock for fermentative production of lactic acid (LA) with Lactobacillus rhamnosus ATCC 7469, a very efficient lactic acid bacterium. Maximum production of lactic acid from RPS was obtained by performing the hydrolysis and fermentation steps simultaneously on medium supplemented with MRS components and calcium carbonate. L. rhamnosus produced 73 g L −1 of lactic acid, corresponding to a maximum productivity of 2.9 g L −1 h −1, with 0.97 g LA produced per g of carbohydrates on initial substrate. A process simplification was also implemented by minimizing RPS supplementation and suppressing Novozym cellobiase addition.

Anaerobic fermentative production of lactic acid using cheese whey and corn steep liquor

Cheese whey was the most suitable substrate for production of lactic acid under anaerobic conditions by Entercoccus flavescens which, on supplementating with corn steep liquor (5% v/v) and 10 mM CaCO(3) at pH 5.5, 37 degrees C, yielded 12.6 g lactic acid/l in 36 h. Production was scaled up to a 10 l bioreactor under controlled pH and continuous CO(2) supply and gave 28 g lactic acid/l in 30 h resulting in a net 8.7-fold increase in production as compared to unoptimized conditions.

Utilization of rice bran as nutrient source for fermentative lactic acid production

To reduce nutrient cost for lactic acid production, rice bran, one of agricultural wastes, was chosen as a nutrient source in this study. Although rice bran is rich in protein and vitamins, the use of rice bran without any treatment was inefficient in lactic acid production. Rice bran was treated by acid-hydrolysis before it was put in experiment, when it was hydrolyzed at initial pH 1, 30 g/L rice bran could provide a productivity to that degree of about 8 g/L YE, showing such a desirable result that the use of rice bran as nutrient source would be a solution for reducing nutrient cost. However, the addition of hydrolyzed rice bran prolonged lag phase of fermentation, especially, in the fermentation with rice bran hydrolyzed at initial pH 0.5, a prolonged lag phase of about 40 h was observed. According to the quantitative determination of thiamine, pyridoxine, organic nitrogen and carbon, the prolongation of lag phase might be the result from the destruction of B vitamins and excessive hydrolysis of protein. To shorten the lag phase, combining hydrolyzed rice bran with yeast extract (YE) of small amount was considered to be a solution. When 3 g/L YE was combined with 30 g/L rice bran hydrolyzed at initial pH 1, obtained was a productivity 1.6 times higher than that of the control fermentation with 15 g/L YE.

Sustainable biocomposites based on autohydrolysis of lignocellulosic substrates

Two xylan-containing lignocellulosic raw materials (rice husks and Eucalyptus globulus wood) were subjected to autohydrolysis under optimised conditions, yielding liquors containing soluble xylan-degradation products and a solid phase enriched in cellulose. Autohydrolysis liquors were acidified with sulfuric acid and heated to yield xylose-containing solutions suitable for the fermentative production of lactic acid, which can be easily converted into polylactic acid (PLA). The solids from autohydrolysis treatments were dried and mixed with PLA (in relative weight proportions 30:70) to give biodegradable composites. The mechanical properties of composites were assessed by tensile and impact tests. Microscopic analysis revealed that the particles of autohydrolysed lignocellulosics were evenly distributed in the PLA matrix. The interfacial compatibility between PLA and reinforcing agents was assessed by scanning electron microscopy.

Fermentative production of lactic acid from biomass: an overview on process developments and future perspectives

The concept of utilizing excess biomass or wastes from agricultural and agro-industrial residues to produce energy, feeds or foods, and other useful products is not necessarily new. Recently, fermentation of biomass has gained considerable attention due to the forthcoming scarcity of fossil fuels and also due to the necessity of increasing world food and feed supplies. A cost-effective viable process for lactic acid production has to be developed for which several attempts have been initiated. Fermentation techniques result in the production of either D: (-) or L: (+) lactic acid, or a racemic mixture of both, depending on the type of organism used. The interest in the fermentative production of lactic acid has increased due to the prospects of environmental friendliness and of using renewable resources instead of petrochemicals. Amylolytic bacteria Lactobacillus amylovorus ATCC 33622 is reported to have the efficiency of full conversion of liquefied cornstarch to lactic acid with a productivity of 20 g l(-1) h(-1). A maximum of 35 g l(-1) h(-1) was reported using a high cell density of L. helveticus (27 g l(-1)) with a complete conversion of 55- to 60-g l(-1) lactose present in whey. Simultaneous saccharification and fermentation is proved to be best in the sense of high substrate concentration in lower reactor volume and low fermentation cost. In this review, a survey has been made to see how effectively the fermentation technology explored and exploited the cheaply available source materials for value addition with special emphasis on lactic acid production.

L-Lactic acid production from apple pomace by sequential hydrolysis and fermentation

The potential of apple pomace (a solid waste from cider and apple juice making factories) as a source of sugars and other compounds for fermentation was evaluated. The effect of the cellulase-to-solid ratio (CSR) and the liquor-to-solid ratio (LSR) on the kinetics of glucose and total monosaccharide generation was studied. Mathematical models suitable for reproducing and predicting the hydrolyzate composition were developed. When samples of apple pomace were subjected to enzymatic hydrolysis, the glucose and fructose present in the raw material as free monosaccharides were extracted at the beginning of the process. Using low cellulase and cellobiase charges (8.5 FPU/g-solid and 8.5 IU/g-solid, respectively), 79% of total glucan was saccharified after 12 h, leading to solutions containing up to 43.8 g monosaccharides/L (glucose, 22.8 g/L; fructose, 14.8 g/L; xylose + mannose + galactose, 2.5 g/L; arabinose + rhamnose, 2.8 g/L). These results correspond to a monosaccharide/cellulase ratio of 0.06 g/FPU and to a volumetric productivity of 3.65 g of monosaccharides/L h. Liquors obtained under these conditions were used for fermentative lactic acid production with Lactobacillus rhamnosus CECT-288, leading to media containing up to 32.5 g/L of l-lactic acid after 6 h (volumetric productivity = 5.41 g/L h, product yield = 0.88 g/g).