Proteolytic Lactic Acid Bacteria Research Articles

Selection of Proteolytic Lactic Acid Bacteria with Probiotic Properties for Fish Protein Hydrolyzate Production

This study aimed to select a proteolytic LAB with probiotic properties that can be applied to manufacture protein hydrolysate from fish heads. Tests on 20 isolates of LAB showed that nine isolates were proteolytic and non-pathogenic. A total of 5 isolates could grow well at 0.5% bile salt stress, and 3 of them could grow at pH 3. These three isolates had antagonistic ability against Salmonella bacteria, and one isolate was sensitive to the antibiotic tested. Molecular identification of the selected LAB isolates showed a 100% sequence similarity with Pediococcus pentosaceus with accession number MT515895.1. The LAB isolate has high proteolytic activity since it can increase the soluble fraction of fish meal powder from 32.10% to 88.38% in 48 hr. Production of protein hydrolysate using tuna waste was carried out for 30 days. Tuna waste protein hydrolysate had a medium antioxidant activity of 25.57 ± 0.93%. The hydrolyzed protein comprised 17 amino acids, including nine non-essential and eight essential amino acids, and is dominated by glutamic acid. Selected LAB isolate is potentially used in protein hydrolysate production, especially for flavor enhancers. Keywords: antagonistic, amino acid, Pediococcus pentosaceus

Isolation and identification of proteolytic lactic acid bacteria from freshwater pomfret (Colossoma macropomum) intestine

The production of freshwater pomfret (Colossoma macropomum) in Indonesia is abundant, but the digestive tract waste weighing 10-15% of the fish body is not widely utilized. The fish's digestive tract can potentially produce lactic acid bacteria (LAB). Lactic acid bacteria have a proteolytic system that can produce extracellular protease enzymes. Protease enzymes are the most widely utilized enzymes in various industries and have a global revenue of up to $2.1 billion in 2021. Protease enzymes derived from microbes are in great demand due to the efficiency of time, place, cost, and better cultivation techniques than animal and plant sources. This study aimed to isolate and identify proteolytic lactic acid bacteria from the intestines of freshwater pomfret fish and determine their proteolytic index. The methods used were morphological, biochemical, sugar, and proteolytic tests. The BAT-A isolate with the highest proteolytic index of 2.52 with characteristics of Gram-positive, non-spore, facultatively anaerobic, catalase-negative, non-motile, homofermentative, can ferment glucose, maltose, lactose and sucrose which were then identified as proteolytic lactic acid bacteria Enterococcus sp which has the potential as a candidate source of protease enzymes from bacteria isolated from the intestines of freshwater pomfret.

Okra seeds proteins: Amino acid profile, free radical scavenging activities and inhibition of diabetes and hypertensive converting enzymes indices

The study was aimed to determine bioactivity of okra seed proteins against oxidative stress, diabetes, and hypertension. Whole okra seed flour (OKPF), protein isolate (OKPI) and hydrolysate (OKPH, using proteolytic Lactic Acid Bacteria) were produced by standard methods. Samples were evaluated for protein contents, amino acids, in-vitro antioxidant, and enzymes (pancreatic lipase, α-amylase, α-glucosidase, and Angiotensin-1 converting) inhibitory properties. Protein content (g/100 g) of OKPH (97.45) was more than OKPI (80.09) and OKPF (26.42). In-vitro protein digestibility indicated that OKPH (87.17%) had the highest value followed by OKPI (77.63%) and OKPF (66.06%), respectively. Amino acid composition (mg/100 g protein), i.e., hydrophobic (32.36), aromatic (7.56), antioxidant (19.15), and branch chain (13.0) in OKPH were higher than in OKPF and OKPI. Functional properties of OKPH showed better attributes than in OKPI and OKPF, respectively. Protein hydrolysate (OKPH) exhibited highest antioxidant and free radical scavenging activity than in OKPI and OKPF. Sample OKPH exhibited highest percentage inhibition against carbohydrate-hydrolyzing and anti-hypertensive enzyme inhibition indices than in OKPF and OKPI. This study established that OKPH exhibited highest antioxidant, pancreatic lipase, angiotensin-1 converting, α-amylase and α-glucosidase enzyme activities. Hence, it may be suitable as nutraceutical agent for antidiabetic and antihypertension.

Molecular and biotechnological characteristics of proteolytic activity from Streptococcus thermophilus as a proteolytic lactic acid bacteria to enhance protein-derived bioactive peptides.

The demand for healthy food items with a high nutrient value of bioavailability and bioaccessibility has created a need for continuous development of technology and food ingredients like bioactive peptides. This study aimed to investigate seven proteolytic lactic acid bacteria (PLABs) isolated from the plaa-som (fermented fish) sample originated from silver BARB species for production of proteolytic enzymes. Proteolytic enzymes produced by (PLABs) were used further to create potent bioactive peptides by hydrolyzing proteins throughout PLAB-probiotics enhancer. Protein derived-bioactive peptides was tested the proteolytic activity on different protein sources and examined bioactivities including antioxidative and antimicrobial effect for further use in functional foods. Results of screened-PLAB strains showed high proteolytic activity namely Streptococcus thermophilus strains (KKUPA22 and KKUPK13). These strains have proteolytic system consisting of extracellular and cell-bound enzymes that used for degrading protein in fish flesh protein (FFP) and skim milk (SKM) broth media. Proteolytic activity of tested bacterial enzymes was estimated after incubation at 45, 37, and 50 °C. Furthermore, FFP hydrolysates were formed with various peptides and has small molecular weights (checked by SDS-PAGE) in the range of10.5 to 22 kDa), exhibiting strong activity. Data revealed that S. thermophilus strains (KKUPA22 and KKUPK13) had high antioxidant activity in term of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical-scavenging inhibition, and ferric reducing antioxidant power (FRAP) reducing power capacity. Both strains (KKUPA22 and KKUPK13) of S. thermophilus have higher antimicrobial activity against Gram-negative bacteria than against Gram-positive bacteria. We have confirmed presence of proteolytic (prt) gene regions in S. thermophilus strains using specific primers via PCR amplification. Results showed highest homology (100%) with the prtS gene of S. thermophillus located on the cell envelope proteolytic enzymes (CEPEs) such as serine proteinase. Therefore, it concluded that the proteolytic system of tested PLAB strains able to generate bioactive peptides-derived proteins having active biological property, good mechanism of degradability, and bioaccessibility for further use in catalyzing protein of functional foods.

ISOLASI DAN KARAKTERISASI BAKTERI PROTEOLITIK ASAL TERASI IKAN SELUANG (Stolephorus sp.)

Anchovy is one type of processed fishery product in Indonesia that is made through a fermentation process. The fish paste fermentation process utilizes the activity of hydrolytic bacteria present in the raw materials. These bacteria can produce hydrolytic enzymes capable of hydrolyzing complex molecules into simple ones. This study aims to isolate proteolytic bacteria and determine the character of the bacterial isolates obtained. The test results were analyzed descriptively. The test parameters carried out were determining the proteolytic index, colony and cell morphology tests, and biochemical tests. 4 bacterial isolates had proteolytic activity, namely PT1, PT2, PT3, and PT5. Based on biochemical tests, the PT2 isolate was suspected to be proteolytic lactic acid bacteria.
 

Single and Co-Cultures of Proteolytic Lactic Acid Bacteria in the Manufacture of Fermented Milk with High ACE Inhibitory and Antioxidant Activities

In this study, single and co-cultures of proteolytic Lactobacillus delberueckii subsp. bulgaricus ORT2, Limosilactobacillus reuteri SRM2 and Lactococcus lactis subsp. lactis BRM3 isolated from different raw milk samples were applied as starter cultures to manufacture functional fermented milks. Peptide extracts from fermented milk samples were evaluated after fermentation and 7 days of cold storage for proteolytic, angiotensin-converting enzyme (ACE) inhibitory and antioxidant activity by different methods including 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), OH-radical scavenging, and total antioxidant (molybdate-reducing activity). The highest proteolysis was found in milk fermented by co-cultures of three strains. Fermentation with the mentioned bacteria increased ACE inhibitory and antioxidant activity of the final products which were dependent on peptide concentration. The crude peptide extract obtained from fermented milk with triple co-culture showed the highest ACE inhibitory activity (IC50 = 0.61 mg/mL) which was reduced after 7 days of cold storage (IC50 = 0.78 mg/mL). Similar concentration-dependent activities were found in antioxidant activity at different antioxidant assays. Overall, high proteolytic activity resulted in increased ACE inhibitory and antioxidant activities, but the highest activity was not necessarily found for the samples with the highest proteolytic activity. The results of this study suggest the potential of using co-cultures of L. delberueckii subsp. bulgaricus, L. reuteri and L. lactis subsp. Lactis to manufacture antihypertensive fermented milk.

Isolation and identification of proteolytic lactic-acid bacteria of the common carp (Cyprinus carpio) by spontaneous fermentation to obtain functional peptides.

High proteolytic activity and several biological functions (antimicrobial, antioxidant, antihypertensive, among others) have been attributed to lactic-acid bacteria (LAB) isolated from fish and peptides obtained from proteolysis. Therefore, the objective of this research was isolating, characterizing, and identifying LAB with proteolytic activity by spontaneous fermentation from common carp (Cyprinus carpio) reared in ponds and wild ones obtained from Lago de Chapala, Jalisco, Mexico. Spontaneous fermentation from complete carp specimens was observed, considering two sampling points (skin and intestines) at 15°C at 5 and 10days. Isolated LAB-from both reared and wild specimens-were identified and morphologically characterized; identification was performed by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Proteolytic activity was assessed by the presence of the proteolytic halo. A total of five genera and eight different LAB proteolytic species were isolated from all the carp samples. At 10days, greater proteolytic LAB diversity was obtained from the intestine (Tukey's, p < 0.05); the proteolytic halo with the greatest diameter was recorded in wild carp skin with Lactiplantibacillus plantarum S5P2 (2.8cm) at 5days of fermentation, followed by Leuconostoc mesenteroides S5I1 (2.73cm) and Leuconostoc pseudomesenteroides S5P2 (2.66cm) (p < 0.05). In conclusion, proteolytic capability of LAB isolated from carp (Cyprimus carpio)-both wild and reared-is influenced by the ecosystem where they develop. These proteolytic LAB may be used in biotechnological industries to obtain bioactive peptides by fermenting substrates rich in proteins.

Isolation and selection of proteolytic lactic acid bacteria from colostrum of dairy cattle

Lactic Acid Bacteria (LAB) are bacteria that produce lactic acid and are very useful bacteria, one of which can act as a probiotic because it can produce bacteriocins and produce peptide compounds with high biological activity. Colostrum is the first fluid that comes out of the udder of the mother cattle after giving birth which is very good for newborns because it contains antibodies. This research aimed to isolate, selection and identify the types of LAB found in dairy cow colostrum, especially LAB which have superior proteolytic activity. LAB obtained is expected to have a positive effect on livestock productivity. This research was conducted In-vitro in a laboratory. The research procedure included the isolation of LAB from the colostrum of dairy cows, then the selection procedure by looking at the best protease enzyme activity qualitatively and quantitatively, and testing for resistance to low pH. Lactic acid isolation, selection, and identification were analyzed using descriptive analysis and quantitative analysis using one-way ANOVA for a completely randomized design. The results obtained 6 superior proteolytic LAB isolates based on the protease enzyme activity coded LAB pro 4, LAB pro 3, LAB pro 8, LAB pro 9, LAB pro 21, and LAB pro 20.

Technological and Safety Attributes of Lactic Acid Bacteria and Yeasts Isolated from Spontaneously Fermented Greek Wheat Sourdoughs.

The aim of the present study was to assess the technological and safety potential of 207 lactic acid bacteria (LAB) and 195 yeast strains isolated from spontaneously fermented Greek wheat sourdoughs. More accurately, the amylolytic, proteolytic, lipolytic, phytase and amino acid decarboxylase activities, along with the production of exopolysaccharides and antimicrobial compounds by the LAB and yeast isolates, were assessed. A well diffusion assay revealed seven proteolytic LAB and eight yeast strains; hydrolysis of tributyrin was evident only in 11 LAB strains. A further Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) indicated partial hydrolysis of gluten. Lipolysis kinetics over 21 days was applied, exhibiting that lipolytic activity ranged from 6.25 to 65.50 AU/mL. Thirteen LAB inhibited Penicillium olsonii and Aspergillus niger growth and 12 yeast strains inhibited Pe. chrysogenum growth. Twenty-one Lactiplantibacillus plantarum strains exhibited inhibitory activity against Listeria monocytogenes, as well as several sourdough-associated isolates. The structural gene encoding plantaricin 423 was detected in 19 Lcb. plantarum strains, while the structural genes encoding plantaricins NC8, PlnE/F, PlnJ/K, and S were detected in two Lcb. plantarum strains. None of the microbial strains tested exhibited exopolysaccharide (EPS) production, amino acid decarboxylase, amylolytic or phytase activity. The technological and safety potential of the Lcb. plantarum and Wickerhamomyces anomalus strains was highlighted, since some of them exhibited proteolytic, lipolytic, antibacterial and antimould activities.

Integrated approach for obtaining bioactive peptides from whey proteins hydrolysed using a new proteolytic lactic acid bacteria

In this study, we investigated the ability of Enterococcus faecalis 2/28, isolated from artisan cheese, to release biopeptides from whey proteins. We used an in silico approach for predicting the bioactivities of peptides generated by E. faecalis. The results of the in vitro study showed that the whey protein hydrolysates (WPHs) obtained had angiotensin-I-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities, with inhibition of ACE being stronger than that of DPP-IV. To identify peptides that may be potential inhibitors of ACE, WPH with the highest ACE inhibitory activity was analysed using Sephadex G-75 gel filtration chromatography, Superdex peptide 10/300 GL size exclusion chromatography, and liquid chromatography-electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS). Among the identified peptides were ACE-inhibitory peptides (LDAQSAPLR, LKGYGGVSLPEW, and LKALPMH), antimicrobial peptides (AASDISLLDAQSAPLR, IIAEKTKIPAVF, IDALNENK, and VLVLDTDYK), DPP-IV-inhibitory peptides (LKALPMH, LKPTPEGDLEIL, LKGYGGVSLPE, LKPTPEGDLE, ILDKVGINY, and VLVLDTDYK), proliferation stimulating peptide (IDALNENK), and cytotoxic peptide (LIVTQTMK).

Physicochemical, microbiological characterization and proteolysis of Algerian traditional Bouhezza cheese prepared from goat’s raw milk

Bouhezza is an Algerian traditional cheese made using different types of milk (goat, sheep and cow), ripened in a goat-skin or sheep-skin bag called Chekoua or Djeld of Bouhezza. The objective of the study was the characterization of Bouhezza cheese through ten cheese preparation trials using goat raw milk. The chemical and microbiological composition and proteolysis were monitored on ripened samples. The physicochemical characteristics showed that Bouhezza is acidic with a pH value of 3.95 and 2.36% for titratable acidity as lactic acid, 13.20% for protein and 12.74% for fat. At the end of ripening, Bouhezza was classified to be a ripened, soft and mid-fat cheese. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) of Bouhezza samples showed low proteolysis after 30 days of ripening. Microbiological results showed a high content of lactic acid bacteria (LAB), 8 to 9 log cfu/ g, an absence of pathogenic bacteria, and a low level of contamination flora. This makes the cheese a healthy product and of an acceptable hygienic quality. Four proteolytic lactic acid bacteria were identified by 16S ribosomal deoxyribonucleic acid (rDNA) sequencing: two strains of Enterococcus faecalis, one E. faecium, and one Lactobacillus paracasei ssp. paracasei. Reversed phase-high performance liquid chromatography (RP–HPLC) of the soluble fraction at pH 4.4 showed changes occurred during ripening. This work highlights, characterizes, and improves the knowledge of cheese Bouhezza made with raw goat's milk. This product is rich in nutrients, such as proteins and minerals, that are useful to the consumer.

Isolation, Screening, and Identification of Proteolytic Lactic Acid Bacteria from Indigenous Chao Product

ABSTRACTThe aim of the study was to isolate, select, and identify proteolytic lactic acid bacteria (LAB) from chao, a traditional fermented fish from Pangkajene and Kepulauan Regency, South Sulawesi, Indonesia. LAB was isolated by poured plate method. Proteolytic LAB were selected using agar skim milk media. Protease activity of LAB was determined based on the amount of tyrosine released in unit/mL. Proteolytic LAB were identified using API 50 CHL kit and 16S rRNA gene sequence analysis. The result showed that a total of 60 isolates were obtained from chao, and 57% of them were cocci-shape. Fifteen isolates were halotolerant proteolytic LAB. Their R values and protease activity were 2.11–3.39 and 0.267–0.304 U/mL, respectively. Identification by API 50 CHL kit showed that four rod-shape isolates were Lactobacillus plantarum, and two others were Lactobacillus curvatus. Cocci-shape isolates could not be identified as cocci bacterium. Rep-PCR results showed that there were two kinds of bands, namely thick and thin. Two isolates were selected from two types of bands that had the highest R for the analysis of 16S rRNA gene sequences, namely Ags1-3 and Ags7-3. The results showed that Ags1-3 isolate was identified as Lactobacillus plantarum and Ags7-3 as Pediococcus acidilactici.

Molecular identification 16S rRNA gene of active proteolytic lactic acid bacteria (LAB) isolated from kelengkeng (Dimocarpus longan) fruit

Abstract. Hidayat H, Haryadi W, Matsjeh S, Raharjo TJ. 2019. Molecular identification 16S rRNA gene of active proteolytic lactic acid bacteria (LAB) isolated from kelengkeng (Dimocarpus longan) fruit. Biodiversitas 20: 2222-2228. Various fermentation food involves microorganisms, especially Lactic Acid Bacteria (LAB) which has beneficial properties for fermented food. The present study aims to do identification and characterization of active proteolytic LAB from kelengkeng (Dimocarpus longan), a commonly found fruit in South East Asia. From ten LAB isolates, isolates K7 and K8 appeared as basil shape based on Gram staining and were chosen for further examination. The molecular identification of these selected isolates were investigated from the 16S rRNA analysis using universal primer 27F and 1525R. The K7 and K8 isolates showed resistance ability towards acidic environment (pH 2.0) and were examined for protease enzyme screening resulting 7.5 and 6 to clear zone, which was 17 and 12 mm. The result of the molecular characterization from the two isolates indicated that isolate K7 was identified as Leuconostoc mesenteroides subsp suionicum strain LT-38 while isolate K8 was identified as Leuconostoc mesenteroides strain C305.16.

Characteristics of proteolytic microorganisms and their effects on proteolysis in total mixed ration silages of soybean curd residue.

ObjectiveThe objective of this study was to isolate proteolytic microorganisms and evaluate their effects on proteolysis in total mixed ration (TMR) silages of soybean curd residue.MethodsTMRs were formulated with soybean curd residue, alfalfa or Leymus chinensis hay, corn meal, soybean meal, a vitamin-mineral supplement, and salt in a ratio of 25.0: 40.0:30.0:4.0:0.5:0.5, respectively, on a basis of dry matter. The microbial proteinases during ensiling were characterized, the dominate strains associated with proteolysis were identified, and their enzymatic characterization were evaluated in alfalfa (A-TMR) and Leymus chinensis (L-TMR) TMR silages containing soybean curd residue.ResultsBoth A-TMR and L-TMR silages were well preserved, with low pH and high lactic acid concentrations. The aerobic bacteria and yeast counts in both TMR silages decreased to about 105 cfu/g fresh matter (FM) and below the detection limit, respectively. The lactic acid bacteria count increased to 109 cfu/g FM. The total microbial proteinases activities reached their maximums during the early ensiling stage and then reduced in both TMR silages with fermentation prolonged. Metalloproteinase was the main proteinase when the total proteinases activities reached their maximums, and when ensiling terminated, metallo and serine proteinases played equally important parts in proteolysis in both TMR silages. Strains in the genera Curtobacterium and Paenibacillus were identified as the most dominant proteolytic bacteria in A-TMR and L-TMR, respectively, and both their proteinases were mainly with metalloproteinase characteristics. In the latter ensiling phase, Enterococcus faecium strains became the major sources of proteolytic enzymes in both TMR silages. Their proteinases were mainly of metallo and serine proteinases classes in this experiment.ConclusionProteolytic aerobic bacteria were substituted by proteolytic lactic acid bacteria during ensiling, and the microbial serine and metallo proteinases in these strains played leading roles in proteolysis in TMR silages.

Brazilian artisanal ripened cheeses as sources of proteolytic lactic acid bacteria capable of reducing cow milk allergy.

The objective was to obtain lactic acid bacteria (LAB) capable of hydrolysing immunoreactive proteins in milk, to optimize the hydrolysis, to determine the proteolysis kinetics and to test the safety of the best hydrolytic strain. Brazilian cheese was used as source of LAB capable of hydrolysing main milk allergens. Proteolytic isolates were submitted to RAPD-PCR for the characterization of clonal diversity. Optimized hydrolysis was strain and protein fraction dependent. 16S rDNA sequencing identified three proteolytic strains: Enterococcus faecalis VB43, that hydrolysed αS1 -, αS2 - and β-caseins, α-lactalbumin and β-lactoglobulin (partial hydrolysis), and Pediococcus acidilactici VB90 and Weissella viridescens VB111, that causedpartial hydrolysis of αS1 - and αS2 -caseins. Enterococcus faecalis VB43 tested negative for virulence genes asa1, agg, efaA, hyl, esp, cylLL and cylLS but positive for genes ace and gelE. Ethylenediamine tetra-acetic acid inhibited the proteolysis, indicating that the main proteases of E. faecalis VB43 are metalloproteases. Brazilian artisanal cheese is a good source of LAB capable of hydrolysing allergenic proteins in milk. One isolate (E. faecalis VB43) presented outstanding activity against these proteins and lacked most of the tested virulence genes. Enterococcus faecalis VB43 presents good potential for the manufacture of hypoallergenic dairy products.

Karakterisasi Bakteri Asam Laktat Proteolitik pada Bekasam

Bekasam is a traditional fermented fish from Indonesia. It is made from fish in which the gills and gut had been discarded, washed, and mixed with salt, after two days, it was covered with rice and salt, and then fermented for 5-7 days at room temperature. Bekasam is perceived to have antihypertensive activity, which is though to be the activity of bioactive peptides, the product of protein degradation during the bekasam fermentation. The research was aim to isolate the indigenous lactic acid bacteria that produce strong proteolytic capabilities. The lactic acid bacteria were collected from 3 kinds of bekasam (tilapia, milkfish, and tuna bekasam). Isolation of the lactic acid bacteria was done on agar medium containing MRS + CaCO3, and the screening of the proteolytic bacteria was done by growing the isolated culture on skim agar. The colonies that produce clear zone were identified as proteolytic lactic acid bacteria. Some of 180 isolated strains of acid producing bacteria that produce clear zone on MRS agar were found 150 strains of lactic acid bacteria, and 84 strains showed their proteolytic activity. The later were identified morphologically and biochemical as Lactobacillus, Pediococcus and Leuconostoc genera. Selection was further conducted based on the height of the proteolytic and homofermentative fermentation activities. Upon species identification using API CH 50 kit, the selected strains belong to species of Lactobacillus plantarum, Lactobacillus pentosus, and Pediococcus pentosaseus.

Fermentative recovery of lipids and proteins from freshwater fish head waste with reference to antimicrobial and antioxidant properties of protein hydrolysate.

Effectiveness of fermentation using lactic acid bacteria (LAB) for recovering lipids and proteins simultaneously from freshwater fish head (FWH) was evaluated. Three different proteolytic LAB (Pediococcus acidilactici NCIM5368, Enterococcus faecium NCIM5335 and Pediococcus acidilactici FD3) isolated from fish processing wastes were employed in the fermentation process. The fermentation conditions involved 10% (w/w) glucose, 2% (w/w) NaCl and 10% (v/w) LAB cultures at 37°C. The process resulted in 38.4% of degree of hydrolysis (in case proteins) and a recovery of 63.6% of the oil present in the material. The fermentation process did not affect the fatty acid profile of lipids. The hydrolyzed protein rich fermentation liquor exhibited DPPH radical scavenging activity (EC50 - 5.1mg protein) as well as antagonistic properties towards several bacterial and fungal pathogens. The minimum inhibitory concentrations (MIC) of fermentated liquor (with E. faecium NCIM5335 as starter) were 10 and 12mg/ml for Listeria monocytogenes and Salmonella itridicus, respectively. A higher MIC (60 and 96mg/ml for Aspergillus ochraceus and Penicillium chrysogenum, respectively) was observed in case of fungal pathogens. Both the oil and protein hydrolysate rich liquor from fish head can be used as biofunctional ingredients in both human food as well as livestock feed formulations.

전통 발효식품으로부터 Protease 활성을 보유한 유산균의 분리 및 동정

A proteolytic lactic acid bacterium was isolated from Korean traditional fermented foods. The isolate BV-26, which had a protease activity (24 U/mg-crude protein), was identified as Lactobacillus plantarum by the API 50CHL kit and 16S rDNA analysis (99.9% of homology), and named as L. plantarum BV-26. Cell growth and protease activity of L. plantarum BV-26 was determined in MRS broth using 5L jar fermentor at 30°C. The maximum growth of L. plantarum BV-26 was reached at 18 hr in MRS broth, while protease activity of BV-26 was detectable at 12 hr and the highest activity was obtained after 16 hr cultivation. Therefore, we expect that the proteolytic lactic acid bacteria, L. plantarum BV-26, may be used as a starter for the fermentation of animal feed. Especially, the fermentation of soybean meal with the strain can be applied for improving feed utilization.

Ability of fermented soymilk by Lactobacillus plantarum 1 in bile acids binding

Some lactic acid bacteria (LAB) strains have been isolated from spontaneously fermented soymilk which showing proteolytic activity. These isolated were expected could producing bioactive peptides that could lowering cholesterol content when they used for soymilk fermentation. This research was aimed to determine the proteolytic activity of Lactobacillus plantarum 1 R.1.3.2 and L. plantarum 1 R.11.1.2 comparing with L. acidophilus FNCC 0051 as a control. Furthermore soymilk fermented with these isolates were monitored for their ability to bind bile acid and these results were compared with the control of soymilk with no fermentation. Proteolytic activities (U/mL) were measured spectrophotometrically using tyrosin as a standard product, while bile acid binding capacity (µM/100 mg protein) using Total bile Acid Binding Kit. The results show that all isolates use in this study had no different proteolytic activity nor bile acid binding capability to that of control strain. The fermentation process could increased their ability to bind with the bile acid. Key words :fermented soymilk, proteolytic lactic acid bacteria, bile acid binding

Antimicrobial peptides generated from milk proteins: a survey and prospects for application in the food industry. A review

Milk proteins constitute a natural reservoir of bioactive peptides with physiological and/or antimicrobial properties, the release of which requires hydrolysis of the precursor molecules by digestive proteases or by fermentation with proteolytic micro‐organisms. Depending on the digestive or microbial proteases used, an array of bioactive peptides would be released either from caseins or whey proteins, but only a small part of these peptides has so far been identified and characterised with respect to their antimicrobial activity. The antimicrobial peptides known thus far have proven to be potent inhibitors to the growth of a wide range of undesirable micro‐organisms of health or spoilage significance. Nevertheless, previous research work has largely been oriented towards their possible application in medicine, which has hindered their high potential as food‐grade biopreservatives and/or as supplements in functional foods. This review attempts to study the literature pertaining to antimicrobial peptides derived from major milk proteins (caseins, α‐lactalbumin and β‐lactoglobulin) upon hydrolysis either by digestive proteases or by fermentation with proteolytic lactic acid bacteria. Their possible application in the food industry and their mechanism of action will also be discussed. Reference antimicrobial peptides produced by living micro‐organisms as innate immune defence components against microbial infections will occasionally be invoked for comparison purposes.