부레옥잠을 이용한 Lactobacillus spp.의 젖산 생산

Lactic acid fermentation from food waste with indigenous microbiota: Effects of pH, temperature and high OLR

Lactic acid is widely used in the food, chemical, textile, and pharmaceutical industries. New applications of lactic acid for the manufacture of biodegradable polymers have increased the demand for it. Lactic acid can be produced from cheese whey and starchy and lignocellulosic biomass via microbial fermentation with lactic acid bacteria (LAB) or fungi. Pure sugar and cheese whey can be directly fermented by lactic acid bacteria, while liquefaction and enzymatic saccharification of starchy biomass and pretreatment and enzymatic hydrolysis of lignocellulosic biomass are required for lactic acid production from biomass. Amylolytic lactic acid bacteria can direct convert starchy biomass to lactic acid. Lactic acid bacteria and methods used for lactic acid production from different feedstocks are summarized in this paper. Lactic acid productivity of 6.34 and 4.87 g/l·h and yields of 0.98 g/g lactose and 0.97 g/g glucose were obtained from cheese whey and wheat starch, respectively, using cell-recycle repeated batch fermentation by Lactobacillus sp. RKY2. Lactic acid bacteria such as Lactobacillus pentosus, Lactobacillus brevis and Lactococcus lactis can ferment glucose to lactic acid by homolactic fermentation and also effectively convert xylose or arabinose to lactic acid and acetic acid by heterolactic fermentation. The process for lactic acid production from lignocellulosic biomass needs to be improved to increase the lactic acid yield and productivity.

The continuous production of lactic acid from deproteinized whey by immobilized single and mixed culture of L. casei and L. lactis in Ca‐alginate beads has been investigated. A coimmobilized culture system gave better results than immobilized single cultures regarding lactic acid concentration, productivity, yield, and lactose utilization. Maximum lactic acid productivity of 7 g/lh was obtained at D=0.4 h−1 with a yield of 70% lactic acid and 50% lactose utilization. At a dilution rate of 0.1 h−1, a lactic acid productivity of 2.5 g/lh was obtained with a 55.5% lactic acid yield and 90% lactose utilization. The bioreactor system was operated at a constant dilution rate of 0.1 h−1 for 20 days without loss of original activity. In this case, the average lactic acid productivity, lactic acid yield and lactose utilization were 24 g/lh, 55% and 90%, respectively.

In this research, five substrates; yam, cassava, corn, potatoes and rice were used for lactic acid fermentation. The microorganisms were isolated using de Mann Rogosa and Sharpe (MRS) medium using the spread plate technique. Ten pure colonies were identified and presumptively classified using standard morphological and biochemical identification processes. After optimizing culture conditions at 35oC, pH 6.0 and fermentation time 122hrs, the effect of Tween 80 supplementation on lactic acid production was investigated. Supplementation of culture medium with Tween 80 was done at two different concentrations (3.0 g/L and 5.0 g/L) and the quantity of lactic acid produced for each concentration determined using total titratable acidity (TTA) method. Tween 80 (3.0 g/L) in the culture medium had dual effects on lactic acid production by the lactic acid bacteria. The highest quantity of lactic acid concentration was produced by Lactobacillus plantarum strain Z2 (0.62 ± 0.01 g/L) in yam fermentation, a 113.7% increase in lactic acid production capacity over that of the un-supplemented yam broth. A percentage increase of 34.5% in lactic acid production capacity was observed for same microorganism (Lactobacillus plantarum strain Z2) in supplemented cassava broth over that of the un-supplemented one. Lactobacillus pentosus strain BSR3 (SL2) produced the highest quantity of lactic acid on the supplemented potatoes broth, a percentage increase of 153% over that of the un-supplemented potatoes broth. For supplemented rice broth, the highest quantity of lactic acid (0.63 ± 0.02 g/L) was produced by Lactobacillus pentosus strain BSR3 (C3P), a percentage increase of 35.9% over that of the un-supplemented rice broth. There was increased lactic acid production by Lactobacillus pentosus strain BSR3 (C3P), Lactobacillus pentosus strain BSR3 (SL2), Lactobacillus plantarum strain FM02 in the Tween 80-supplemented corn broth. However, there were decreases in lactic acid production by Lactobacillus pentosus strain BSR3 (C3P) in cassava broth, by Lactobacillus plantarum strain Z2 in both corn and potato broths supplemented with the Tween 80 at 3.0 g/L. The addition of Tween 80 at 5.0 g/L resulted in decreased lactic acid production. The percentage reduction in descending order of lactic acid production in yam, cassava, corn, potatoes and rice broths by Lactobacillus plantarum strain Z2 were 79.3%, 83.6%, 90.9%, 70% by Lactobacillus pentosus strain BSR3 (SL2) and 86.9% (Lactobacillus pentosus strain BSR3 (C3P)) respectively. For un-supplemented broths, Lactobacillus plantarum strain Z2 produced the highest lactic acid (0.56 ± 0.35 g/L) from potatoes broth. With supplementation of broths with Tween 80 (at 3.0 g/L), lactic acid production was enhanced, with Lactobacillus pentosus strain BSR3 (SL2) producing the highest lactic acid concentration (0.76 ± 0.01 g/L) from potato broth. It is recommended, for large-scale production of lactic acid, that potatoes broth be fermented with Lactobacillus pentosus strain BSR3 (SL2) under the optimized culture conditions.

In the current work, date wastes were used for lactic acid (LA) production under thermo-alkaline conditions to overcome some fermentation challenges. Amongst 27 bacterial isolates that produced LA from date juice, isolate D-218 exhibited better growth stability and LA production under various stressed conditions. This isolate was characterized as Bacillus coagulans D-218 using physiological and molecular identification methods. In batch fermentation mode, strain D-218 could not completely utilize 80 g/L of the total sugar and produced only 45.8 ± 2.8 g/L of LA at LA productivity of 0.214 g/L.h and high residual sugar (29.2 g/L) was unutilized in the fermentation media. Different repeated batch fermentations with different initial sugar concentrations and gradual increase in sugar concentrtions were conducted to maximize LA productivity. Starting with 60 g/L of total sugar, four runs of repeated batch fermentations were conducted that enhanced the LA productivity (70%) to 0.49 g/L.h. Another 9 runs were initiated with 40 g/L which further improved LA productivity that reached up to 0.77 g/L.h. Surprisingly, initiating fermentations with 20 g/L of total sugar successfully attained long-term fermentation (18 runs) with high LA yield and productivity without carbon loss of initiated startup sugar of date waste. In this process, strain D-218 could completely consume 80 g/L sugars with high LA production titer (72.9 ± 0.56 g/L), yield (0.92 g/g), and productivity (0.71 g/L.h). This study is the first to exploit date waste in a cost-effective system for high-titer lactic acid production under thermo-alkaline conditions (pH 9.0; 50 °C) and to report repeated batch fermentation for LA production from date wastes.

Originally, lactic acid was produced from pure starch or from glucose. Increasingly, however, agricultural feedstocks such as grains and green biomass are also being used as raw materials for the production of microbial 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 lactate productivity for cultivation on a barley hydrolyzate medium was examined. The parameter optimization showed that the strain Lactobacillus paracasei 168 can achieve a maximum productivity of 11.8 g/(L h), in batch cultivation on a nutrient enriched MRS medium, at a temperature of 39 °C and a pH value of 6.3. However, this parameter optimum does not correspond to the parameter optimum of lactate yield (96.8 %, T = 30 °C, pH 5.75). In order to define working points for the large‐scale production of lactic acid, parameter combinations which guarantee high values of both lactate productivities (≥ 8 g/(L h)) and lactate yields (≥ 92 %) in a short process duration (≤ 35 h) were predicted by means of three‐dimensional model equations. As a consequence, productivities of 8 g/(L h)–11 g/(L h) with lactate yields of 93–95 % can be achieved with the strain L. paracasei 168. Cultivation on MRS barley hydrolyzate medium resulted in production data with about the same range of values as those obtained with the MRS medium. Under these conditions, this strain accumulated more than 100 g of lactate/L in the medium. Medium optimization experiments showed that the main components of the nitrogen containing nutrients in the MRS medium (peptone and yeast extract) can be replaced by protein extracts from green biomass (lucerne green juice). This positive result for the utilization of different renewable resources in lactic acid fermentation has to be confirmed and optimized for the continuous mode and pilot scale, respectively.

Tailoring non-axenic lactic acid fermentation from cheese whey permeate targeting a flexible lactic acid platform

BackgroundThe increasing interest in probiotic lactobacilli in health maintenance has raised the question of potential risks. One possible side effect could be an increased acidogenicity in dental plaque. The aim of this study was to investigate the effect of probiotic lactobacilli on plaque lactic acid (LA) production in vitro and in vivo.MethodsIn the first part (A), suspensions of two lactobacilli strains (L. reuteri DSM 17938, L. plantarum 299v) were added to suspensions of supragingival dental plaque collected from healthy young adults (n=25). LA production after fermentation with either xylitol or fructose was analyzed. In the second part (B), subjects (n=18) were given lozenges with probiotic lactobacilli (L. reuteri DSM 17938 and ATCC PTA 5289) or placebo for two weeks in a double-blinded, randomized cross-over trial. The concentration of LA in supragingival plaque samples was determined at baseline and after 2 weeks. Salivary counts of mutans streptococci (MS) and lactobacilli were estimated with chair-side methods.ResultsPlaque suspensions with L. reuteri DSM 17938 produced significantly less LA compared with L. plantarum 299v or controls (p<0.05). Fructose gave higher LA concentrations than xylitol. In part B, there were no significant differences in LA production between baseline and follow up in any of the groups and no differences between test and placebo were displayed. The salivary MS counts were not significantly altered during the intervention but the lactobacilli counts increased significantly in the test group (p<0.05).ConclusionLactic acid production in suspensions of plaque and probiotic lactobacilli was strain-dependant and the present study provides no evidence of an increase in plaque acidity by the supply of selected probiotic lactobacilli when challenged by fructose or xylitol. The study protocol was approved by The Danish National Committee on Biomedical Research Ethics (protocol no H-2-2010-112).Trial registrationNCT01700712

Lactic acid bacteria (LAB) are the most important bacteria in desirable food fermentations, being responsible for the fermentation of sourdough bread, fermented foods and beverages, all fermented milks and fermented vegetables. They play essential roles in the production of all dairy products and is involved in the production of many other fermented foods and beverages, sausages, pickles, etc. This study aimed to produce lactic acid using lactic acid bacteria isolated from pap “akamu” and liquid milk samples. The following procedures were conducted to achieve the objectives of the study, which include sample collection, isolation of lactic acid bacteria (LAB) from samples, screening of LAB for lactic acid production, characterisation of selected lactic acid bacteria, and optimisation of process parameters for lactic acid production. Results from the study showed that the highest lactic acid production (6.39 mg/ml) from milk samples was observed from an isolate from milk sample 2, while for the pap samples, the highest lactic acid production (2.79 mg/ml) was observed from an isolate from pap sample 4. The highest lactic acid producers from the milk and pap samples were identified based on their macroscopic, microscopic and molecular characteristics. The bacteria were identified as Lactobacillus paracasei (sample milk 2) and Levilactobacillus brevis (sample pap 4). Biochemical characterisation indicated the metabolic capabilities of these isolates, including acidifying properties, enzyme production, and fermentation abilities. The highest production of lactic acid by co-cultures of Lactobacillus paracasei and Levilactobacillus brevis was observed after 96 h of incubation. Enhanced lactic acid yield by the co-cultures was observed at pH 5.5 (8.6 mg/ml), while the lactic acid production decreased at a higher pH. The lactic acid concentration increased to the optimum lactic acid value (8.60 mg/mL) at 35°C, then decreased at 45°C. Maximum lactic acid production of 11.2mg/ml was observed at 200 rpm, the least of 4.9 mg/ ml was observed at zero or no agitation. The lactic acid production increased gradually with increasing inoculum size up to the maximum value (10.7 mg/mL) at 5% inoculum size. Lactic acid actually had the highest peak area, retention time and concentration in the GCFID chromatogram, while the other components had low values, further revealing the successful extraction of the lactic compound. The results of the present study indicated that the co-cultures of Lactobacillus paracasei (milk 2) and Levilactobacillus brevis (pap 4) isolated from milk and akamu, respectively, hold significant potential for lactic acid production.

In this study, we found that p-coumaric acid (p-CA), ferulic acid (FA), and condensed tannins were released from rice straw during saccharification. The presence of polyphenols prolonged the lag phase and lowered the productivity of lactic acid. p-CA was identified as a key inhibitor. Tannins had a lower inhibitory effect than p-CA; FA had little inhibitory effect. Acid, alkaline, and ball milling pretreatments elicited different levels of polyphenol release from rice straw. Due to the different levels of polyphenol release in the pretreatment step, the enzymatic hydrolysates contained different concentrations of polyphenols. Compared with fermentation with a synthetic medium, fermentation with the hydrolysates of ball-milled rice straw provided much lower productivity and yield of lactic acid due to the presence of polyphenols. Removal of these compounds played an important role in lactic acid fermentation. When rice straw was alkaline pretreated, the hydrolysates contained few phenolic compounds, resulting in high productivity and yield of lactic acid (1.8g/L/h and 26.7g/100g straw), which were comparable to those in a synthetic medium. This indicates that there is a correlation between removal of phenolic compounds and efficiency in lactic acid fermentation.

Lactic acid production through fermentation is an established technology, however, improvements are necessary to reduce the process costs and to decrease its market price. Lactic acid is used in many industrial sectors and its market has increased in the last decade for its use as the raw material for polylactic acid product. Using food waste as a cheap and renewable substrate, as well as fermentation at uncontrolled pH, helps to make the production cheaper and to simplify the downstream purification process. Lactic acid production at acidic conditions and the role of varying organic loading rate (OLR) and hydraulic retention time (HRT) were tested in two different semicontinuous batch fermentation systems. Reactor performances indicated that lactic acid fermentation was still possible at pH < 3.5 and even up to a pH of 2.95. The highest lactic acid production was recorded at 14-day HRT, 2.14 g VS/L·day OLR, and pH 3.11 with a maximum lactic acid concentration of 8.72 g/L and a relative yield of 0.82 g lactate/g carbohydrates. The fermentation microbial community was dominated by Lactobacillus strains, the organism mainly responsible for lactic acid conversion from carbohydrates. This study shows that low pH fermentation is a key parameter to improve lactic acid production from food waste in a semicontinuous system. Acidic pH favored both the selection of Lactobacillus strains and inhibited VFA producers from utilizing lactic acid as primary substrate, thus promoting the accumulation of lactic acid. Finally, production yields tend to decrease with high OLR and low HRT, while lactic acid production rates showed the opposite trend.

Continuous mix batch bioreactors were used to study the kinetic parameters of lactic acid fermentation in microaerated-nutrient supplemented, lactose concentrated cheese whey using Lactobacillus helveticus. Four initial lactose concentrations ranging from 50 to 150 g l−1 were first used with no microaeration and no yeast extract added to establish the substrate concentration above which inhibition will occur and then the effects of microaeration and yeast extract on the process kinetic parameters were investigated. The experiments were conducted under controlled pH (5.5) and temperature (42 °C) conditions. The results indicated that higher concentrations of lactose had an inhibitory effect as they increased the lag period and the fermentation time; and decreased the specific growth rate, the maximum cell number, the lactose utilization rate, and the lactic acid production rate. The maximum lactic acid conversion efficiency (75.8%) was achieved with the 75 g l−1 initial lactose concentration. The optimum lactose concentration for lactic acid production was 75 g l−1 although Lactobacillus helveticus appeared to tolerate up to 100 g l−1 lactose concentration. Since the lactic acid productivity is of a minor importance compared to lactic acid concentration when considering the economic feasibility of lactic acid production from cheese whey using Lactobacillus helveticus, a lactose concentration of up to 100 g l−1 is recommended. Using yeast extract and/or microaeration increased the cell number, specific growth rate, cell yield, lactose consumption, lactic acid utilization rate, lactic acid concentration and lactic acid yield; and reduced the lag period, fermentation time and residual lactose. Combined yeast extract and microaeration produced better results than each one alone. From the results it appears that the energy uncoupling of anabolism and catabolism is the major bottleneck of the process. Besides lactic acid production, lactose may also be hydrolysed into glucose and galactose. The β-galactosidase activity in the medium is caused by cell lysis during the exponential growth phase. The metabolic activities of Lactobacillus helveticus in the presence of these three sugars need further investigation.

Lactic Acid as a platform chemical has broad application in various industries, especially in the production of Poly Lactic Acid (PLA) for biodegradable plastic. Empty fruit bunch (EFB), abundant by product from palm oil mill industry, is one of potential feedstock to be used in the production of lactic acid from lignocellulose biomass. EFB contains high cellulose and hemicellulose about 37– 59.7% w/w and 16–28% w/w, respectively. The aim of this paper is to study the effects of the operating conditions, such as temperature, reaction time, biomass loading, and catalyst concentration on the yield of lactic acid using barium hydroxide as alkaline catalyst. EFB pretreatment with steam explosion was applied to remove lignin content. The results showed that pretreatment reduced the lignin content from 22.66% to 9.69% w/w. Meanwhile, hemicellulose and cellulose increased from 14.40% to 16.40% w/w and 29.37% to 63.57% w/w, respectively. The highest yield of lactic acid was 21.57% C-mol, achieved by using 0.25 M Ba(OH)2 as the catalyst, with 5% w/v biomass loading, temperature 240°C, during 4 h reaction times. The yield was approximately equal to yield of lactic acid (~ 20%) compared with Pb2+ as the catalyst for EFB conversion although the later catalyst produced fewer by products during conversion.

Efficient lactic acid production from cassava bagasse by mixed culture of Bacillus coagulans and lactobacillus rhamnosus using stepwise pH controlled simultaneous saccharification and co-fermentation

BACKGROUNDUtilization of wastes and industrial by‐products for production of valuable bio‐based chemicals has economic and environmental advantages. The aim of this study was to investigate utilization of two industrial by‐products, distillery stillage and sugar beet molasses combined as a substrate for lactic acid and biomass production. A selection of the most appropriate lactic acid bacteria that could effectively utilize this waste substrate was performed. In addition, the effect of initial sugar concentration on lactic acid production and growth of lactic acid bacteria on the combined waste substrate was evaluated.RESULTSLactobacillus paracasei NRRL B‐4564 was selected as the most promising for lactic acid production on distillery stillage and sugar beet molasses. The highest lactic acid productivity of 1.42 g L−1 h−1 and yield of 0.91 g g−1 were achieved on stillage/molasses media at initial sugar concentration of 56.74 g L−1. The highest number of L. paracasei cells at 5.3 × 109 CFU mL−1 was achieved at initial sugar concentration of 78.22 g L−1.CONCLUSIONCombined distillery stillage and sugar beet molasses could provide valuable nutrients for growth of fastidious lactic acid bacteria and enable efficient lactic acid production, while processing industrial waste in this way has great environmental relevance. © 2015 Society of Chemical Industry