Optimization of bacteriocin production by Lactobacillus sp. MSU3IR against shrimp bacterial pathogens

BACKGROUND: Aquaculture is one amongst the growing and major food producing sectors. Shrimp culture is one of the subsectors of aquaculture that attracts more attention because of the economic interest. However, the shrimp culture systems have been facing severe consequences and economical losses due to disease outbreaks. Risk of disease outbreak can be combated with the application of probiotics. For economically viable production of such probiotic products, the present study provides information on the optimization and partial purification of bacteriocin produced by a goat milk isolate Lactobacillus sp. MSU3IR against the shrimp bacterial pathogens. RESULTS: Bacteriocin production was estimated as a measure of bactericidal activity (arbitrary Unit/ml) over the test strains. The optimum culture conditions and media components for maximum bacteriocin production by Lactobacillus sp. MSU3IR were: pH: 5.0, temperature: 30°C, carbon source: lactose; nitrogen source: ammonium acetate; NaCl: 3.0% and surfactant: Tween 80. MRS medium was found to extend better bacteriocin production than other tested media. Upon partial purification of bacteriocin, the SDS-PAGE analysis had manifested the presence of two peptide bands with the molecular weight of 39.26 and 6.38 kDa, respectively. CONCLUSION: The present results provide baseline trend for the statistical optimization, scale up process and efficient production of bacteriocin by the candidate bacterial strain Lactobacillus sp. MSU3IR which could be used to replace the usage of conventional chemotherapeutics in shrimp culture systems

Proizvodnja lipaze s pomoću bakterije Serratia rubidaea izolirane iz mlijeka

Production of extracellular lipase in submerged culture of Serratia rubidaea has been investigated. The lipase production was optimized in shake flask experiments. The observed pH and temperature range optimum for maximum lipase production were 7–8 and 30–40 °C, respectively. With a selected nitrogen source, casein ((6.5±0.015) U/mL) and soytone ((9.4±0.02) U/mL) were suitable substrates for accelerating lipase production. The optimized concentration of casein and soytone was 24 g/L ((9.95±0.02) U/mL) and 5 g/L ((14.8±0.03) U/mL), respectively. The effect of carbon source on lipase production indicated that starch was suitable substrate to maximize lipase production ((15.60±0.20) U/mL) and the optimum concentration registered was 4 g/L ((17.46±0.20) U/mL). Investigating the effect of lipids and surfactants showed that the gingily oil ((20.52±0.20) U/mL) and Tween 20 ((27.10±0.01) U/mL) were suitable substrates for maximizing lipase production, and the optimum concentrations registered were 15 mL/L ((23.15±0.24) U/mL) and 6 mL/L ((34.20±0.01) U/mL), respectively. Partial purification of lipase indicated that the molecular mass of partially purified enzyme was 54 kDa.U radu je istražena proizvodnja ekstracelularne lipaze pri submerznom uzgoju bakterije Serratia rubidaea, optimirana pokusima na tresilici. Za maksimalnu proizvodnju lipaze optimalna pH-vrijednost bila je 7-8, a optimalna temperatura 30-40 °C. Primjenom kazeina ((6,5±0,015) U/mL) i peptona iz soje ((9,4±0,02) U/mL) kao izvora dušika, pospješena je proizvodnja lipaze. Optimirana koncentracija kazeina iznosila je 24 g/L ((9,95±0,02) U/mL), a peptona iz soje 5 g/L ((14,8±0,03) U/mL). Za maksimalnu proizvodnju lipaze ((15,60±0,20) U/mL) najbolji izvor ugljika bio je škrob, pri optimalnoj koncentraciji od 4 g/L ((17,46±0,20) U/mL). Ispitivanje utjecaja lipida i površinski aktivnih tvari pokazalo je da su sezamovo ulje ((20,52±0,20) U/mL) i Tween 20 ((27,10±0,01) U/mL) najprikladniji supstrati za maksimalnu proizvodnju lipaze. Optimalni volumni udio sezamovog ulja bio je 15 mL/L ((23,15±0,24) U/mL), a Tweena 20 je bio 6 mL/L ((34,20±0,01) U/mL). Djelomično pročišćavanje lipaze pokazalo je da je njezina molekularna masa 54 kDa

Antifouling and toxic properties of the bioactive metabolites from the seagrasses Syringodium isoetifolium and Cymodocea serrulata

International audienceThe present study documents the antifouling and toxic properties of seagrasses Syringodium isoetifolium and Cymodocea serrulata. For that, the seagrasses S. isoetifolium and C. serrulata were extracted individually using organic solvents viz. dichloromethane, acetone and methanol. Amongst the extracts, the maximum antimicrofouling and antimacrofouling activities were exhibited by methanol extracts of both the seagrasses. The Minimal Inhibitory Concentration (MIC) of methanolic extracts of seagrasses was ranged from 1.0 to 10 mu g/ml against test biofilm bacteria and microalgal strains. Similarly, 100% fouling inhibition of limpet Patella vulgata was found at 6.0 mg/ml of methanolic extracts of seagrasses. The mussel Perna indica showed 50% of byssal production and attachment inhibition at 21.51 +/- 2.03, 17.82 +/- 1.07 mu g/ml and the anticrustaecean activity for 50% mortality of Anemia sauna was recorded at 732.14 +/- 921 and 394.16 +/- 5.16 mu g/ml respectively for methanolic extracts of S. isoetifolium and C serrulata. The minimal inhibitory and higher lethal concentrations of active methanol extracts shows it's less toxic nature. Based on the prolific results, methanol extracts of S. isoetifolium and C serrulata were subjected to purification using silica gel column and thin layer chromatography. Then the active compounds of the bioassay guided fractions were partially characterized using gas chromatography coupled with mass spectroscopy (GC-MS) and keyed out that fatty acids (C-16 to C-24) were the major components which responsible for the antifouling properties of the candidate seagrasse

Investigation of Lipase Production by Milk Isolate Serratia rubidaea

Production of extracellular lipase in submerged culture of Serratia rubidaea has been investigated. The lipase production was optimized in shake flask experiments. The observed pH and temperature range optimum for maximum lipase production were 7–8 and 30–40 °C, respectively. With a selected nitrogen source, casein ((6.5±0.015) U/mL) and soytone ((9.4±0.02) U/mL) were suitable substrates for accelerating lipase production. The optimized concentration of casein and soytone was 24 g/L ((9.95±0.02) U/mL) and 5 g/L ((14.8±0.03) U/mL), respectively. The effect of carbon source on lipase production indicated that starch was suitable substrate to maximize lipase production ((15.60±0.20) U/mL) and the optimum concentration registered was 4 g/L ((17.46±0.20) U/mL). Investigating the effect of lipids and surfactants showed that the gingily oil ((20.52±0.20) U/mL) and Tween 20 ((27.10±0.01) U/mL) were suitable substrates for maximizing lipase production, and the optimum concentrations registered were 15 mL/L ((23.15±0.24) U/mL) and 6 mL/L ((34.20±0.01) U/mL), respectively. Partial purification of lipase indicated that the molecular mass of partially purified enzyme was 54 kDa

TBT Effects on the Development of Intersex (Ovotestis) in Female Fresh Water Prawn Macrobrachium rosenbergii

The impact of tributyltin (TBT) on the female gonad and the endocrine system in Macrobrachium rosenbergii was studied. Prawns were exposed to environmentally realistic concentrations of 10, 100, and 1000 ng/L of TBT for 6 months. Dose dependent effects were noticed in TBT exposed prawns. At 1000 ng/L TBT caused ovotestis formation (formation of male germ cells in ovary). Presence immature oocytes, fusion of developing oocytes, increase in interstitial connective tissues, and its modification into tubular like structure and abundance of spermatogonia in the ovary of TBT treated prawns. The control prawn ovary showed normal architecture of cellular organelles such as mature oocytes with type 2 yolk globules, lipid droplets, normal appearance of yolk envelop, and uniformly arranged microvilli. On the other hand, type 1 yolk globules, reduced size of microvilli, spermatogonial cells in ovary, spermatogonia with centrally located nucleus, and chromatin distribution throughout the nucleoplasm were present in the TBT treated group. Immunofluorescence staining indicated a reduction in vitellin content in ovary of TBT treated prawn. Moreover, TBT had inhibited the vitellogenesis by causing hormonal imbalance in M. rosenbergii. Thus, the present investigation demonstrates that TBT substantially affects sexual differentiation and gonadal development in M. rosenbergii