Simultaneous lactic acid and xylitol production from vine trimming wastes

Hemicellulosic hydrolyzates from vineshoot trimmings obtained by dilute sulfuric acid hydrolysis were evaluated for xylitol production by Debaryomyces hansenii NRRL Y‐7426. Bioconversion was not efficient, however, since a mixture of products (mainly ethanol) was achieved. Taking into account that hexoses (such as glucose or mannose) can inhibit xylose metabolism by repression and inactivation of the xylose transport system or catabolic enzymes and that these hemicellulosic hydrolyzates are characterized by a high glucose concentration, a novel technology was developed, sequentially transforming glucose into lactic acid by Lactobacillus rhamnosus followed by fermentation of xylose into xylitol by Debaryomyces hansenii after L. rhamnosus removal by microfiltration. Optimal conditions were achieved using detoxified concentrated hemicellulosic hydrolyzates, after CaCO₃ addition in both stages of fermentation and using nitrogen purges after sampling in order to reduce the oxygen dissolved. Under these conditions 31.5 g lactic acid L^?1 (Q_LA = 1.312 g L^?1 h^?1 and Y_LA/S = 0.93 g g^?1) and 27.5 g xylitol L^?1 (Q_Xylitol = 0.458 g L^?1 h^?1 and Y_Xylitol/S = 0.53 g g^?1) were produced. Finally, lactic acid was selectively recovered using the resin Amberlite IRA 400 (0.0374 g of lactic acid g^?1 of dry resin), allowing a further recovery of xylitol by sequential stages of adsorption, concentration, ethanol precipitation, concentration and crystallization to obtain food‐grade xylitol according to a developed process. Copyright © 2007 Society of Chemical Industry     

Use of spent brewer's yeast in L‐(+) lactic acid fermentation

The application of by‐products from the brewing industry in lactic acid (LA) production was investigated in order to replace expensive nitrogen sources (such as yeast extract) with cheaper and renewable nitrogenous materials such as brewer's yeast (BY). In this study, brewer's spent grain (BSG) hydrolysate was used for L‐(+)‐LA fermentation by Lactobacillus rhamnosus ATCC 7469. The effect of pH control during the fermentation and the addition of various BY contents (5–50 g/L) in BSG hydrolysate on fermentation parameters was evaluated. BY addition significantly increased free amino nitrogen (FAN) concentration (by 25.2% at 5 g/L to 616% at 50 g/L). A strong positive correlation between FAN concentration in the hydrolysate and concentration of L‐(+)‐LA produced was observed (correlation coefficient of 0.913). A high cell viability of L. rhamnosus ATCC 7469 (1.95–3.32 × 10⁹ CFU/mL at the end of fermentation) was achieved in all fermentations with the addition of brewer's yeast. The addition of BY increased L‐(+)‐lactic acid yield and volumetric productivity up to 8.4% (5 g/L) and 48.3% (50 g/L). The highest L‐(+)‐LA yield (89%) and volumetric productivity (0.89 g/L h^?1) were achieved in fermentation of BSG hydrolysate with 50 g/L of BY. © 2019 The Institute of Brewing & Distilling     

Production of L‐Lactic Acid from Spent Grain,a By‐Product of Beer Production

L‐lactic acid production from spent grain with immobilized lactic acid bacteria was investigated. Spent grains were liquefied by a steam explosion treatment to obtain liquefied sugar. When 1 kg of wet spent grain was treated under the 30 kg/cm²pressure for 1 min using a 5‐L steam explosion reactor, 60 g of total sugar was obtained from the liquefied spent grain. Furthermore, 1.3% (w/v) of glucose, 0.4% (w/v) of xylose, and 0.1% (w/v) of arabinose were produced when the liquefied spent grain was treated with glucoamylase, cellulase, and hemicellulase enzymes. When batch L‐lactic acid production was carried out by Lactobacillus rhamnosus NBRC14710, 19.0 g/L L‐lactic acid was produced from the Tween 80 liquefied spent grain after 5 days. Furthermore, during repeated batch production with immobilized Lactobacillus rhamnosus NBRC14710 from Tween 80 liquefied spent grain at 37°C, the productivity of L‐lactic acid was maintained at a 10 time higher level over a period of 40 days.     

Integral utilisation of barley husk for the production of food additives

A new and effective chemical–biotechnological process for the global utilisation of barley husk (obtained from the spent grains in the brewing process) is reported. With the proposed process the three main components of the lignocellulosic residue (cellulose, hemicellulose and lignin) are utilised. A first treatment with sulfuric acid (pre‐hydrolysis) allowed the solubilisation of hemicelluloses to give xylose and glucose‐containing liquors (suitable to make fermentation media for the continuous lactic acid (LA) production with L. pentosus) and a solid phase containing cellulose and lignin. In this set of experiments, a maximum volumetric productivity (Q_P) = 2.077 g L^?1 h^?1 and product yield (Y_P/S) = 0.62 g g^?1 were obtained for a dilution rate of 0.01 h^?1. The solid residues from pre‐hydrolysis were treated with NaOH in order to increase their cellulase digestibility, and dissolve the lignin content. The cellulose residue was used as substrates for lactic acid production by simultaneous saccharification and fermentation (SSF) in media containing Trichoderma reesei cellulases and Lactobacillus rhamnosus cells using the complete MRS broth or a cheaper medium. In both cases similar LA concentrations and volumetric productivities were achieved (P = 73.4–71.0 g L^?1 and Q_P = 1.28–1.25 g L^?1 h^?1, respectively), where P is LA concentration. The lignin solution obtained after the alkaline treatment was extracted with ethyl acetate in order to obtain the phenolic components. The extract obtained at pH 3 showed three times more antioxidant activity than the one extracted at pH 12.8, with an EC₅₀ of 1.396 g L^?1 for pH 3 and 4.604 g L^?1 for pH 12.8. The best extracts showed twice antioxidant activity than BHT. Copyright © 2007 Society of Chemical Industry     

Production of a Lactobacillus plantarum starter with linamarase and amylase activities for cassava fermentation

Lactobacillus plantarum strain A6 isolated from cassava, cultured on cellobiose MRS medium showed a growth rate of 0.41 h^?1, a biomass yield of 0.22 g g^?1, and produced simultaneously an intracellular linamarase (76.4 U g^?1 of biomass) and an extracellular amylase (36 U ml^?1). The synthesis of both enzymes was repressed by glucose. The use of such a strain as a cassava fermentation starter for gari production had the following influences: a change from a hetero-fermentative pattern observed in natural fermentation to a homofermentation, a lower final pH, a faster pH decline rate and a greater production of lactic acid (50 g kg^?1 DM). However, this starter did not appear to play a significant role in cassava detoxification, since it was observed that the level of endogenous linamarase released during the grating of the roots was sufficient to permit the complete and rapid breakdown of linamarin.     

Use of waste materials for Lactococcus lactis development

BACKGROUND: Lactococcus lactis is an interesting microorganism with several industrial applications, particularly in the food industry. As well as being a probiotic species, L. lactis produces several metabolites with interesting properties, such as lactic acid (LA) and biosurfactants. Nevertheless, L. lactis is an especially demanding species since it has strong nutritional requirements, implying the use of complex and expensive culture media. RESULTS: The results showed the potential of L. lactis CECT‐4434 as a LA and biosurfactant producer. The economical cost of L. lactis cultures can be reduced by replacing the MRS medium by the use of two waste materials: trimming vine shoots as C source, and 20 g L^?1 distilled wine lees (vinasses) as N, P and micronutrient sources. From the hemicellulosic fraction, 14.3 g L^?1 LA and 1.7 mg L^?1 surfactin equivalent were achieved after 74 h (surface tension reduction of 14.4 mN m^?1); meanwhile, a simultaneous saccharification and fermentation process allowed the generation of 10.8 g L^?1 LA and 1.5 mg L^?1 surfactin equivalent after 72 h, reducing the surface tension by 12.1 units at the end of fermentation. CONCLUSIONS: Trimming vine shoots and vinasses can be used as alternative economical media for LA and cell‐bound biosurfactant production. Copyright © 2010 Society of Chemical Industry     

The effect of inoculation and additives on D(−)‐ and L(+)‐lactic acid production and fermentation quality of guineagrass (Panicum maximum Jacq) silage

Two experiments were carried out to study the influence of storage time, glucose and urea additions ( Experiment 1 ) and lactic acid bacteria inoculation with and without glucose addition ( Experiment 2 ) on the production of lactate isomers and fermentation quality of guineagrass (Panicum maximum Jacq) silage. All silages in both experiments were well preserved, as indicated by lower pH and little or no butyric acid. In Experiment 1 , addition of glucose or urea did not significantly affect the pH of silages (P > 0.05). Urea addition tended to reduce acetic acid content and greatly increased NH₃ − N content. L (+)‐Lactic acid was produced predominantly in the first 3 days of ensiling, but D (−)‐lactic acid increased gradually until 1 month after ensiling. Thereafter all silages became stable. In Experiment 2 , inoculation of Lactobacillus casei or L rhamnosus with or without glucose reduced D (−)‐lactic acid and increased L (+)‐lactic acid of silages. The proportions of L (+)‐lactic acid in these silages were higher than 80% of total lactic acid. L plantarum alone or in combination with glucose promoted D (−)‐lactic acid production and decreased the proportion of L (+)‐lactic acid. Glucose addition alone tended to reduce the proportion of L (+)‐lactic acid in both experiments. © 2000 Society of Chemical Industry     

Physicochemical and microbiological description of Caxiri – a cassava and corn alcoholic beverage

Caxiri is a fermented alcoholic beverage made from cassava, corn and sweet potatoes by indigenous people in Brazil. Saccharomyces cerevisiae Rhodotorula mucilaginosa, Lactobacillus fermentum, Bacillus subtilis and L. helveticus were the main microbial species detected. Maltose was the main carbohydrate found (19.12 g L^?1), and lactic acid (15.09 g L^?1) and ethanol (92.16 g L^?1) were also found in high concentrations. Gas chromatography‐flame ionisation detector was used to identify thirteen volatile compounds. Among these volatiles, the higher concentrations were decanoic acid (123.04 μg L^?1) for the acids, diethyl malate (88.32 μg L^?1) for the esters, furfural (109.31 μg L^?1) for the aldehydes, 2‐phenylethanol (1022.76 μg L^?1) for the alcohols and 1,1‐diethoxyethane (226.24 μg L^?1) for the others. This study contributes to increasing knowledge of the microbiota present in the alcoholic fermentation produced from cassava, corn and sweet potatoes.     

Lactic acid production using waste generated from sweet potato processing

Organic waste generated from industrial sweet potato canning is estimated to be 30% of incoming raw material with significant residual carbohydrate content. The purpose of this study was to evaluate the potential of waste generated from sweet potato processing material to support the growth of lactic acid bacteria and the production of lactic acid. The waste was comprised of 16.5% solids consisting of 18.5% ash, 4.4% protein, 20.5% simple sugars and 19% soluble starch. Following a screening of three lactic acid bacteria strains, Lactobacillus rhamnosus was deemed the best candidate for lactic acid production. The potential of various dilutions of the enzyme‐hydrolysed waste, with and without pH control, as a fermentation substrate was evaluated. Lactic acid production was highest in hydrolysed waste (without dilution) at pH set point 5.0, yielding 10 g L^?1 in 72 h. Thus, lactic acid, a valuable organic compound, can be generated from sweet potato waste.     

Assessment of hydrolysis of cheese whey and use of hydrolysate for bioproduction of carotenoids by Sporidiobolus salmonicolor CBS 2636

BACKGROUND: The increasing industrial demand for carotenoids has led to growing interest in their bioproduction. The need to reduce production costs has encouraged the use of low‐cost agroindustrial substrates. In this context, this work studied the pretreatment of Mozzarella cheese whey and the use of the pretreated whey as fermentation medium for the bioproduction of carotenoids by Sporidiobolus salmonicolor CBS 2636. RESULTS: Bioproduction was carried out in an orbital shaker using a 10 mL L^?1 inoculum, incubation at 25 °C and a stirring rate of 180 rpm for 120 h in a non‐illuminated environment. The carotenoids were recovered using liquid N₂ combined with dimethyl sulfoxide for cell rupture and an acetone/methanol mixture (7:3 v/v) for extraction. The maximum concentration of total carotenoids obtained was 590.4 µg L^?1 in a medium with 900 g L^?1 cheese whey hydrolysate and 4 g L^?1 K₂HPO₄ at 180 rpm, 25 °C and pH 4. CONCLUSION: The use of enzyme‐hydrolysed cheese whey was more effective in carotenoid bioproduction by S. salmonicolor CBS 2636 than the use of acid‐hydrolysed cheese whey. The concentration of total carotenoids obtained with the enzymatic hydrolysate was six times higher than that obtained with the acid hydrolysate. Copyright © 2009 Society of Chemical Industry     

Effect of calcium chloride on mechanical properties and microbiological characteristics of cv. Conservolea naturally black olives fermented at different sodium chloride levels

The effect of calcium chloride (CaCl₂)(5 gL^?1) and sodium chloride (NaCl) concentration (40, 60 and 8 gL^?1) on the microbiological and mechanical properties of naturally black olives of cv. Conservolea in brines was studied. In 40 and 60 g L^?1 brines the growth of lactic acid bacteria was favoured over that of yeasts, resulting in rather complete lactic acid fermentation as indicated by high free acidity (9.8–11.5 g lactic acid L^?1) and low pH (3.7–3.8). At 80 g L^?1 brine, yeasts were the dominant members of the microflora, rendering a product with lower acidity (8 g lactic acid L^?1) and higher pH (4.3–4.5). In the presence of CaCl₂ there was a consistent increase in the depth of the peripheral region in which cell wall breakage occurred. When cells separated, perforated walls were observed at sites associated with plasmodesmata. The flesh was strongest and stiffest when CaCl₂ was added to olives treated with 40 g L^?1 brine, consistent with cell wall breakage being the predominant mode of failure. The only observed effect on the mechanical properties of the skin was a stiffening at 60 g L^?1 brine on addition of CaCl₂. Copyright © 2007 Society of Chemical Industry     

Sensorically and antimicrobially active metabolite production of Lactobacillus strains on Jerusalem artichoke juice

BACKGROUND: In the tubers of Jerusalem artichoke (Helianthus tuberosus L.) the main carbohydrate is the well‐known prebiotic inulin, which is a good growth substrate for gut microorganisms. Jerusalem artichoke tuber is traditionally consumed boiled or pickled rather than in fermented form. Lactic acid bacteria are traditionally used in the production of fermented foods; nevertheless their behavior and metabolite production are considerably influenced by the substrate. The purpose of this study was to investigate the growth and production of the most important sensorically and antimicrobially active metabolites of different Lactobacillus strains on Jerusalem artichoke juice. RESULTS: All investigated strains grew well (in the range 10⁹ cfu mL^?1) in the media. The organic acids (lactic acid, 110–337 mmol L^?1; acetic acid, 0–180 mmol L^?1; and succinic acid, 0–79 mmol L^?1), hydrogen peroxide (0.25–1.77 mg L^?1), mannitol (0.06–3.24 g L^?1), acetoin and diacetyl production of strains varies not only according to the species but also from strain to strain, which will be demonstrated and discussed in the paper. CONCLUSION: Our results showed that lactobacilli can be used for the fermentation of Jerusalem artichoke, which in this form could be used, alone or mixed with other raw food material, as a new synbiotic functional food. Copyright © 2011 Society of Chemical Industry     

Chemical composition and sensory analysis of cheese whey‐based beverages using kefir grains as starter culture

The aim of the present work was to evaluate the use of the kefir grains as a starter culture for tradicional milk kefir beverage and for cheese whey‐based beverages production. Fermentation was performed by inoculating kefir grains in milk (ML), cheese whey (CW) and deproteinised cheese whey (DCW). Erlenmeyers containing kefir grains and different substrates were statically incubated for 72 h at 25 °C. Lactose, ethanol, lactic acid, acetic acid, acetaldehyde, ethyl acetate, isoamyl alcohol, isobutanol, 1‐propanol, isopentyl alcohol and 1‐hexanol were identified and quantified by high‐performance liquid chromatography and GC‐FID. The results showed that kefir grains were able to utilise lactose in 60 h from ML and 72 h from CW and DCW and produce similar amounts of ethanol (～12 g L^?1), lactic acid (～6 g L^?1) and acetic acid (～1.5 g L^?1) to those obtained during milk fermentation. Based on the chemical characteristics and acceptance in the sensory analysis, the kefir grains showed potential to be used for developing cheese whey‐based beverages.     

Application of the Weibull model to describe inactivation of Listeria monocytogenes and Escherichia coli by citric and lactic acid at different temperatures

Inactivation of Listeria monocytogenes and Escherichia coli by citric (10‐150 g L^?1) and lactic (1‐60 mL L^?1) acids at different temperatures (4, 20, 40 °C) has been investigated. Bactericidal effect of both acids was dependent on time and temperature of exposure and acid concentration. Survival curves of L. monocytogenes treated by lactic acid were concave downward and those treated by citric acid were linear. On the other hand, survival curves of E. coli treated by both organic acids were concave upward. Shape of survival curves depended on the type of acid but not on the treatment temperature. A mathematical model based on the Weibull distribution accurately described the kinetics of inactivation of both microorganisms by both acids. This model allowed quantification and comparison of the acid resistance of L. monocytogenes and E. coli. Lactic acid was more effective than citric acid and E. coli was more sensitive to both acids than L. monocytogenes. Copyright © 2006 Society of Chemical Industry     

Selection of lactic acid bacteria for acidification of brown juice (grass juice), with the aim of making a durable substrate for L‐lysine fermentation

BACKGROUND: Brown juice is a waste product from the green crop‐drying industry. Heating and pressing of green crops prior to drying produces a juice rich in nutrients, which can be converted to a stable universal fermentation medium by lowering its pH to 4.0–4.5 via lactic acid fermentation. The aim of this study was to select a strain of lactic acid bacteria for industrial acidification of brown juice. RESULTS: Several strains were tested in fermentation experiments and Lactobacillus salivarius ssp. salivarius DSM 20555 was found to be the best choice. It showed high growth rates at temperatures ranging from 40 to 48 °C, with an optimum temperature of 46 °C (µ_max = 2.2 h^?1), and maintained a high productivity at pH 4.0 in continuous fermentation. The highest productivity of 7.23 g L^?1 h^?1 was found at a dilution rate of 1.0 h^?1. CONCLUSION: With today's increased focus on utilisation of residues from food and agro‐industry, coupled with restrictions on their use as fertiliser for farmlands, lactic acid fermentation could play a significant role in conservation of these nutrient‐rich liquids. This study shows that Lb. salivarius ssp. salivarius DSM 20555 is a very promising micro‐organism for use in such a process. Copyright © 2008 Society of Chemical Industry     

The influence of calcium-carbonate and yeast extract addition on lactic acid fermentation of brewer's spent grain hydrolysate

Brewer's spent grain (BSG) is the major by-product of the brewing industry, representing around 85% of the total by-products generated. In this study BSG hydrolysate was produced using optimal conditions. Hydrolysates were used for lactic acid (LA) fermentation by Lactobacillus fermentum (PL-1) and Lactobacillus rhamnosus (ATCC 7469). The aim of this study was to evaluate possibilities of the BSG hydrolysate utilization as a substrate for LA fermentation. The effect of calcium-carbonate (2%) and yeast extract (0.5 to 5%) addition in hydrolysate on LA fermentation were investigated. The LA production by L. fermentum and L. rhamnosus in BSG hydrolysate was influenced by calcium-carbonate and yeast extract supplementation. L. fermentum produced a racemic mixture of L-(+)- and D-(−)-LA while L. rhamnosus produced mostly L-(+)-LA (95–98%) in all fermentations. Calcium-carbonate addition increased total LA yield by 13% in L. fermentum fermentations and by 17% in L. rhamnosus fermentations. Yeast extract addition increased total LA yield by 4–26% in L. fermentum fermentations and by 6–8% in L. rhamnosus fermentations.     

Co-production of Lactic Acid and <Emphasis Type="Italic">Lactobacillus rhamnosus</Emphasis> Cells from Whey Permeate with Nutrient Supplements

Lactic acid and cell production from whey permeate by Lactobacillus rhamnosus with different nutrient supplements were investigated in this study. Yeast extract was identified as the most effective nutrient affecting lactic acid production. Increase in inoculum size from 0.05% to 1% (v/v) resulted in a substantial increase in lactic acid productivity from 0.66 to 0.83 g L⁻¹ h⁻¹ (P < 0.001). The optimal temperature for lactic acid production was 37 °C, while the highest cell production was obtained at 42 °C. When whey permeate and yeast extract concentrations were 6.8% (w/v) and 3 g L⁻¹, respectively, lactic acid productivity reached 0.85 g L⁻¹ h⁻¹ after 48-h cultivation, which is 3.40 times of those without nutrient supplements.     

Brewers' spent grain and thin stillage as raw materials in l‐(+)‐lactic acid fermentation

Brewer's spent grain (BSG) hydrolysates were used for l ‐(+)‐lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. In this study the effect of the addition of various amounts of thin stillage (TS) in BSG hydrolysate on LA fermentation parameters were evaluated. TS addition significantly increased utilization of glucose by up to 43.0%. In batch fermentation the highest LA concentration and volumetric productivity of 31.0 g/L, and 0.93 g/L/h, respectively, were obtained with the addition of 50% TS. L. rhamnosus cell viability also increased with the addition of 50% TS (by 2.4%). TS addition significantly increased free amino nitrogen concentration (by up to 209%) which is important for bacterial growth. A strong positive correlation between free amino nitrogen and LA concentration was noted. Compared with the results obtained in the batch fermentation (50% TS), significantly higher LA concentration, yield and volumetric productivity (54.8, 1.9 and 4.0%, respectively) were achieved in fed‐batch fermentation with glucose and TS addition. The results suggest that the combination of the by‐products of brewing and bioethanol industries could be suitable for LA production. Copyright © 2017 The Institute of Brewing & Distilling     

Biotechnological potential of industrial wastes for economical citric acid bioproduction by Aspergillus niger through submerged fermentation

Submerged citric acid (CA) bioproduction was carried out by Aspergillus niger NRRL‐567 using various industrial wastes, such as brewery spent liquid (BSL), lactoserum and starch industry water sludge. CA bioproduction was carried out by varying the temperature (25–35 °C), pH (3–5), addition of inducers, incubation time and supplementation with different proportions of apple pomace ultrafiltration sludge (APS). The results indicated that under the best conditions with 3% (v/v) methanol, the optimal concentration of 11.34 g L^?1 CA was recorded using BSL at pH 3.5 and temperature 30 °C after 120‐h incubation period. Supplementation of methanol resulted in an increase of 56% CA production. Meanwhile, under similar conditions, higher concentration of 18.34 g L^?1 CA was reported with the supplementation of BSL with 40% (v/v) APS having suspended solids concentration of 30 g L^?1. The present study demonstrated the potential of BSL supplemented with APS as an alternative cheap substrate for CA fermentation.     

Production of fermentable media from vine‐trimming wastes and bioconversion into lactic acid by Lactobacillus pentosus

Trimmings of vineshoots, an agricultural waste with little use, were hydrolysed with dilute sulphuric acid (1–5%) in order to obtain sugar solutions suitable as fermentation media. The operational conditions for hydrolysis were selected on the basis of both the generation of hemicellulosic sugars (mainly xylose) and glucose and the concentrations of reaction byproducts affecting fermentation (furfural, hydroxymethylfurfural and acetic acid). Hemicellulosic hydrolysates were supplemented with nutrients and fermented with Lactobacillus pentosus, without any previous detoxification stage, to produce lactic acid. Under the best operational conditions assayed (3% H₂SO₄ and 15 min), 21.8 g lactic acid l^?1 was produced (Q_P = 0.844 g l^?1 h^?1, Y_P/S = 0.77 g g^?1), which represents a theoretical yield of 99.6%. Acetic acid was the primary byproduct formed from xylose, at about 25% of the lactic acid level. Copyright © 2004 Society of Chemical Industry