Nitrogen Source Concentration Research Articles

Optimatization in Bioconversion of Quercetin Glucosides Using Aspergillus acueletus LS04-3

Microbial transformation is known to be useful for obtaining more active or less toxic compounds and achieving selective compounds conversion to more useful derivatives. The objective of this study is to explore several factors that affect the optimization of bioconversion of quercetin glucosides using Aspergillus acueletus LS04-3. To obtain the optimum condition of biotransformation the fungus was cultured under several conditions by varying the number of days of fermentation, the concentration of substrate, carbon, and nitrogen source. The transformation product was analyzed using HPLC and LCMS-MS. The results revealed that on the third-day biotransformation process, quercetin production reached the highest amount and the optimum concentration was at 50 ppm of quercetin glucoside based on HPLC analysis. In addition, from various carbon sources, glucose yielded the highest biotransformation product, while nitrogen accelerated the reaction. In this research, media of A. acueletus LS04-3 containing carbon and nitrogen could increased quercetin production. This research finding provided several factors for optimizing quercetin biotransformation by A. acueletus LS04-3. These factors were important in scaling up biotransformation even in other biotransformation reactions.

Optimisation of Lactic Acid Fermentation from Cassava Peel by Lactobacillus casei (ATCC334)

The demand for lactic acid is steadily increasing due to the desire of its bioproduction over chemical synthesis. The associated cost, however, is a significant hurdle. This study reports lactic acid fermentation by Lactobacillus casei ATCC334 from cassava peel. It investigates the effect of unhydrolysed cassava peels, acidic, alkali hydrolysates; fermenting pH; substrate concentration; nitrogen source concentration; duration; and inoculum size. An attempt at a cheaper purification and recovery protocol relative to those currently in use was similarly performed. Acidic hydrolysate yielded 10.53%, unhydrolysed substrate gave 4.80% with alkali hydrolysate yielding 4.75%. The highest LA yield was obtained at pH 6.0, 2.0% v/v inoculum size, 25% w/v substrate concentration, 5% nitrogen source concentration. A post-optimisation combination yielded 18.3% LA suggesting that one-factor-at-a-time may be unsuitable for optimisation studies involving cassava peel and L. casei ATCC334. FTIR spectra of product suggests effective partial purification. Hence, an improvement in the optimization strategy for production is recommended for subsequent study.

Production of microbial carotenoids by Rhodotorula lactosa isolated in the Brazilian tropical savanna / Produção de carotenoides microbianos por Rhodotorula lactosa isolada na savana tropical brasileira

Exploration of new biomes to obtain microorganisms of industrial interest can reveal a number of new strains but they are not all equally efficient in their carotenoids production under different environmental conditions. Screening is needed to select the elite strain and thus commercially produce the pigment. The main objective of this study was to increase the carotenoid production capacity of a recently isolated yeast obtained from the Cerrado (Brazilian tropical savanna) biome. Four hundred and seventy yeast colonies were isolated, of which 25 were pigment-producing yeasts. The promising yeast was identified, by molecular analysis (polymerase chain reaction - PCR) as Rhodotorula lactose, presenting 4.0 g/L of biomass and 776.67 µg/L (194.17 µg/g) of carotenoids (volumetric and specific) in the commercial medium. In the optimization, the carbon source (43 g/L of glucose) was the most significant and positive factor in the carotenoid production process (1318.27 µg/L and 145.58 µg/g), followed by the concentration of nitrogen sources (0.7 g/L yeast extract and 0.7 g/L peptone). The equation generated from the optimized process was validated and showed similar values in the carotenoid production (1233.80 µg/L and 156.60 µg/g) proving it to be promising process model for a scale-up using submerged culture.

Efficient Decolorization of Dye Acid Blue 113 by Soil Bacterium <i>Bacillus subtilis</i> RMLP2

In this study, a bacterial strain was isolated from soil and tested for the decolorization of azo dye Acid Blue 113 (AB 113). Decolorization of azo dyes by means of physico-chemical method is not environmentally friendly thus an alternative method based on bacteria was employed for decolorization of AB 113. The color removal studies were performed using Bushnell and Hass medium amended with AB 113 dye. Bacterial isolate Bacillus subtilis RMLP2 was identified by 16S rRNA gene sequence analysis. The effect of various physico-chemical parameters such as incubation condition, pH, temperature, carbon source, nitrogen source and dye concentration on decolorization of AB 113 by Bacillus subtilis RMLP2 were studied. The bacterial isolate showed the remarkable higher percentage (92.71%) of color removal of dye AB 113 at 100 mg/L concentration, 35oC, pH 7 during 72 h of incubation period under static condition. Yeast extract and glucose was found as best nitrogen and carbon source for efficient decolorization of dye. These results confirmed that the Bacillus subtilis has enormous ability to degrade dye AB 113 present in textile effluents.

Nitrogen content reduction on scenedesmus obliquus biomass used to produce biocrude by hydrothermal liquefaction

The use of Microalgae biomass for biofuel production by hydrothermal liquefaction (HTL) has been proposed as an alternative to traditional fossil fuels. When comparing fossil fuels, Microalgae biocrude has a high nitrogen content, which is one of the challenges that affect this technology. This factor causes operational issues because it lowers the carbon fraction in the chemical composition, which reduces the calorific value and, as a result, raises NOx emissions during combustion.In this work, conditions were established for obtaining Microalgae biomass to allow the production of biocrude with low nitrogen content by HTL. The effect of the variation in nitrogen levels on the culture medium, on cell growth and nitrogen content, was evaluated in the final biomass for the Scenedesmus obliquus strain; at a laboratory scale, the best results (around 0.25 g/L NaNO3) were used at a bench scale with 20 L tubular photobioreactors (PBRs). The remaining biomass was processed through HTL then the resulting biocrude was characterized. The results show that as the nitrogen source in the culture medium increases, the percentage of nitrogen in the remaining biomass and the biocrude produced also increases. It was possible to establish a concentration of nitrogen source in the culture medium that promotes the accumulation of lipids, decreases the protein content in the final biomass and consequently, in the biocrude, without affecting production and yield, a critical factor to take into consideration when assessing the viability of the proposed process.

Isocitric Acid Production from Ethanol Industry Waste by Yarrowia lipolytica

There is ever increasing evidence that isocitric acid can be used as a promising compound with powerful antioxidant activity to combat oxidative stress. This work demonstrates the possibility of using waste product from the alcohol industry (so-called ester-aldehyde fraction) for production of isocitric acid by yeasts. The potential producer of isocitric acid from this fraction, Yarrowia lipolytica VKM Y-2373, was selected by screening of various yeast cultures. The selected strain showed sufficient growth and good acid formation in media with growth-limiting concentrations of nitrogen, sulfur, phosphorus, and magnesium. A shortage of Fe2+ and Ca2+ ions suppressed both Y. lipolytica growth and formation of isocitric acid. The preferential synthesis of isocitric acid can be regulated by changing the nature and concentration of nitrogen source, pH of cultivation medium, and concentration of ester-aldehyde fraction. Experiments in this direction allowed us to obtain 65 g/L isocitric acid with a product yield (YICA) of 0.65 g/g in four days of cultivation.

PEPC of sugarcane regulated glutathione S-transferase and altered carbon\u2013nitrogen metabolism under different N source concentrations in Oryza sativa

BackgroundPhosphoenolpyruvate carboxylase (PEPC) plays an important role in the primary metabolism of higher plants. Several studies have revealed the critical importance of PEPC in the interaction of carbon and nitrogen metabolism. However, the function mechanism of PEPC in nitrogen metabolism is unclear and needs further investigation.ResultsThis study indicates that transgenic rice expressing the sugarcane C4-PEPC gene displayed shorter primary roots and fewer crown roots at the seedling stage. However, total nitrogen content was significantly higher in transgenic rice than in wild type (WT) plants. Proteomic analysis revealed that there were more differentially expressed proteins (DEPs) responding to nitrogen changes in transgenic rice. In particular, the most enriched pathway “glutathione (GSH) metabolism”, which mainly contains GSH S-transferase (GST), was identified in transgenic rice. The expression of endogenous PEPC, GST and several genes involved in the TCA cycle, glycolysis and nitrogen assimilation changed in transgenic rice. Correspondingly, the activity of enzymes including GST, citrate synthase, 6-phosphofructokinase, pyruvate kinase and ferredoxin-dependent glutamate synthase significantly changed. In addition, the levels of organic acids in the TCA cycle and carbohydrates including sucrose, starch and soluble sugar altered in transgenic rice under different nitrogen source concentrations. GSH that the substrate of GST and its components including glutamic acid, cysteine and glycine accumulated in transgenic rice. Moreover, the levels of phytohormones including indoleacetic acid (IAA), zeatin (ZT) and isopentenyladenosine (2ip) were lower in the roots of transgenic rice under total nutrients. Taken together, the phenotype, physiological and biochemical characteristics of transgenic rice expressing C4-PEPC were different from WT under different nitrogen levels.ConclusionsOur results revealed the possibility that PEPC affects nitrogen metabolism through regulating GST, which provide a new direction and concepts for the further study of the PEPC functional mechanism in nitrogen metabolism.

Bioprocess Optimisation for High Cell Density Endoinulinase Production from Recombinant Aspergillus niger.

Endoinulinase gene was expressed in recombinant Aspergillus niger for selective and high-level expression using an exponential fed-batch fermentation. The effects of the growth rate (μ), glucose feed concentration, nitrogen concentration and fungal morphology on enzyme production were evaluated. A recombinant endoinulinase with a molecular weight of 66 kDa was secreted. Endoinulinase production was growth associated at μ> 0.04 h-1, which is characteristic of the constitutive gpd promoter used for the enzyme production. The highest volumetric activity (670 U/ml) was achieved at a growth rate of 93% of μmax (0.07 h-1), while enzyme activity (506 U/ml) and biomass substrate yield (0.043 gbiomassDW/gglucose) significantly decreased at low μ (0.04 h-1). Increasing the feed concentration resulted in high biomass concentrations and viscosity, which necessitated high agitation to enhance the mixing efficiency and oxygen. However, the high agitation and low DO levels (ca. 8% of saturation) led to pellet disruption and growth in dispersed morphology. Enzyme production profiles, product (Yp/s) and biomass (Yx/s) yield coefficients were not affected by feed concentration and morphological change. The gradual increase in the concentration of nitrogen sources showed that, a nitrogen limited culture was not suitable for endoinulinase production in recombinant A. niger. Moreover, the increase in enzyme volumetric activity was still directly related to an increase in biomass concentration. An increase in nitrogen concentration, from 3.8 to 12 g/L, resulted in volumetric activity increase from 393 to 670 U/ml, but the Yp/s (10053 U/gglucose) and Yx/s (0.049 gbiomasDWs/gglucose) did not significantly change. The data demonstrated the potential of recombinant A. niger and high cell density fermentation for the development of large-scale endoinulinase production system.

Growth Optimisation and Kinetic Profiling of Diesel Biodegradation by a Cold-Adapted Microbial Consortium Isolated from Trinity Peninsula, Antarctica.

Simple SummaryDiesel fuel is very crucial for anthropogenic activities in Antarctica and the surges in annual demand mean higher likelihood of spillages from improper handling during transportation, storage and disposal processes. The impacts can be very extensive or well-contained depending on the scale of the spills as well as the terrain involved. Nevertheless, the freezing temperature and prolonged solar irradiance in the south pole greatly hampered the natural attenuation and photovolatilisation of petrogenic hydrocarbons, contributing to their persistency. The most susceptible groups are the soil microorganisms, mosses, seabirds and pinnipeds as they are easily found near the shore where hydrocarbons spillage is very common. Microbial bioremediation is a well-established approach in restoring many hydrocarbons-polluted areas, thus the current study focused on the optimisation and application of locally isolated microbial consortium to simulate the in situ diesel clean-up process in aqueous medium. This study highlights the ability of the selected consortium to degrade diesel almost completely at moderately low temperature, suggesting its potential application in Antarctic settings.Pollution associated with petrogenic hydrocarbons is increasing in Antarctica due to a combination of increasing human activity and the continent’s unforgiving environmental conditions. The current study focuses on the ability of a cold-adapted crude microbial consortium (BS24), isolated from soil on the north-west Antarctic Peninsula, to metabolise diesel fuel as the sole carbon source in a shake-flask setting. Factors expected to influence the efficiency of diesel biodegradation, namely temperature, initial diesel concentration, nitrogen source type and concentration, salinity and pH were studied. Consortium BS24 displayed optimal cell growth and diesel degradation activity at 1.0% NaCl, pH 7.5, 0.5 g/L NH4Cl and 2.0% v/v initial diesel concentration during one-factor-at-a-time (OFAT) analyses. The consortium was psychrotolerant based on the optimum growth temperature of 10‒15 °C. In conventionally optimised media, the highest total petroleum hydrocarbons (TPH) mineralisation was 85% over a 7-day incubation. Further optimisation of conditions predicted through statistical response-surface methodology (RSM) (1.0% NaCl, pH 7.25, 0.75 g/L NH4Cl, 12.5 °C and 1.75% v/v initial diesel concentration) boosted mineralisation to 95% over a 7-day incubation. A Tessier secondary model best described the growth pattern of BS24 in diesel-enriched medium, with maximum specific growth rate, μmax, substrate inhibition constant, Ki and half saturation constant, Ks, being 0.9996 h−1, 1.356% v/v and 1.238% v/v, respectively. The data obtained suggest the potential of microbial consortia such as BS24 in bioremediation applications in low-temperature diesel-polluted soils.

Green synthesis of bioemulsifier and exopolysaccharides by Brevibacillus borstelensis and process parameters optimization using response surface model, genetic algorithm and NSGA

Bioemulsifier and exopolysaccharides are industrially important biomolecules produced by microorganisms using green technology. They have applications in food, biomedical, pharmaceutical and cosmetic industries and hence high yield of both products becomes necessary. The current study showed that Brevibacillus borstelensis has a potential to produce bioemulsifier and exopolysaccharide simultaneously but yield of both products is limited. In this study, CCD-RSM has been used as experimental design to increase concentration of both products. Concentrations of glucose, monosodium glutamate, yeast extract and magnesium sulphate were process variables and concentrations of bioemulsifiers, exopolysaccharides and biomass were responses. 30 experimental runs were performed and the models from CCD were optimized by genetic algorithm and NSGA. The results from modelling and optimization techniques were compared along with validation of models. The predicted values from optimization techniques were better than experimental values. The study concluded that NSGA is most suitable to optimize multiple responses simultaneously when compared to RSM and genetic algorithm. The optimum conditions for production were 22 g/l glucose, 14 g/l monosodium glutamate, 6 g/l yeast extract and 0.6 g/l magnesium sulphate with maximum yield of 6.1, 17.6 and 2.8 g/l bioemulsifier, exopolysaccharide and biomass, respectively. Knowledge of optimum concentrations of carbon and nitrogen source will help to utilize industrial and agricultural wastes for production of both products. They have applications in environmental bioremediation by clearing oil spills. Bioemulsifiers also help in heavy metal removal from hazardous waste. Hence this will result in environmental bioremediation by utilization of wastes by employing products generated from wastes.

Lignocellulolytic bacteria isolated from organic rice field soils for enzyme production using agricultural wastes: Screening, medium optimization, and co-culture

Lignocellulolytic bacteria can degrade agricultural biomass and fungal cell walls. Organic agriculture intensively employs these microbes as biofertilizers and biocontrol agents. This study focused on isolating, screening, identifying, and optimizing enzyme production of the lignocellulolytic bacteria obtained from organic rice field soils for utilizing in organic farming. Here we have shown that the farming periods can alter the bacterial biodiversity in organic rice field soil by providing different nutrients. Paenibacillus polymyxa BTK01 and Bacillus subtilis BTK07, which were isolated from the preharvest soil, exhibited a high activity of mannanase (MNN) and xylanase (XLN). By optimizing the enzyme production, BTK01 and BTK07 were specifically productive in xylanase and mannanase, respectively, because of the induction of substrate-like carbon sources. Varying the type and concentration of nitrogen source revealed that mannanase production positively correlated to bacterial growth of both strains. Throughout the study, we used soybean meal as a nitrogen source with the nitrogen concentration of 0.144% (w/v), BTK01 was productive in xylanase when cultured in the medium comprised of 1.5% (w/v) rice straw (0.905 ± 0.016 U/mL), and BTK07 was efficient in mannanase production when cultured in the medium consisted of 1.0% (w/v) copra meal (0.440 ± 0.000 U/mL). The co-culture of BTK01 and BTK07 using the volume ratio of 1:10 could yield MNN and XLN to be 2.470 ± 0.013 and 0.906 ± 0.015 U/mL, respectively. This result demonstrates that Paenibacillus polymyxa BTK01 and Bacillus subtilis BTK07 can be useful and applicable for organic agriculture as biocontrol agents and biofertilizers.

Optimization of culture conditions for cellulase production in Acanthophysium Sp. KMF001 using response surface methodology

There are differences in the extracellular enzymes produced from species of wood-rotting fungi and their activity due to variation in nutritional conditions such as carbon sources and nitrogen sources, as well as environmental conditions such as incubation temperature and pH. In this study, to determine the methods to promote the secretion of especially cellulase with high activity among the extracellular enzymes of wood-damaging fungi, the optimal nutrient sources and incubation conditions for the production of cellulase with high activity were investigated using response surface methodology based on a broth culture from Acanthophysium sp. KMF001, a novel strain of wood-damaging fungus. The nutrient sources that were optimal for the cellulase production with high activity from Acanthophysium sp. KMF001 were cellulose as a carbon source and tryptone:yeast extract (7:3) as a nitrogen source. The optimal incubation conditions were a temperature of 30 °C and a pH of 6. The optimal concentrations of carbon and nitrogen sources were cellulose at 31.1 g∙L-1 and tryptone:yeast extract (7:3) at 15 g∙L-1, with pH of 5.9.

INVESTIGATION OF FERMENTATION CONDITION FOR PRODUCTION ENHANCEMENT OF POLYHYDROXYALKANOATE FROM CHEESE WHEY BY PSEUDOMONAS SP.

A newly acquired polyhydroxyalkanoate (PHA) producing Pseudomonas sp. was characterized based on 16S rRNA gene sequences (1,423 bp) and identified as P. Putida SS9. This strain P. putida SS9 was considered in respect of its potential for achieving maximum production of PHA under controlled volumetric oxygen transfer coefficient (kLa) using inexpensive substrate, cheese whey. The significant parameters such as pH, temperature, nitrogen source concentration were studied in shake flask. The influence of aeration and agitation on kLa and production of PHA was studied in stirred tank fermenter. Maximum PHA concentration of 5.98 and 4.33 g/l was obtained using cheese whey medium (CWM) and mineral salts medium (MSM) respectively. Further, the properties of PHA were analyzed by Differential scanning calorimetry, Thermal gravimetry analysis. The structure of the compound was elucidated by Fourier transform infrared and Nuclear magnetic resonance spectroscopy. The findings suggested that the cheese whey could be a most excellent alternative carbon source for PHA production using P. putida SS9 and thus it could effectively replace the synthetic mineral salts medium under optimum kLa. The nucleotide sequence proclaimed in this work will emerge in the GenBank nucleotide sequence database under accession number MF403057.

Pemanfaatan sumber nitrogen organik dalam pembuatan nata de coco

Nata de coco is made from raw coconut water which is fermented using the Acetobacter xylinum bacteria. This product has the characteristics of a white color, a thickness of approximately 1-2 cm and a chewy texture like a gel. The largest content in nata de coco is fiber known as bacterial cellulose. In addition to requiring sugar as a carbon source, making nata de coco also requires a source of nitrogen to activate the extracellular enzymes of the Acetobacter xylinum bacteria in the manufacture of nata cellulose. Sources of nitogen used in the manufacture of nata de coco generally use inorganic nitrogen sources, which in their development have caused many pros and cons, especially with regard to food safety issues when this product is consumed as a beverage. This study aims to obtain the best alternative nitrogen source and concentration in making nata de coco. The experimental design used in this study was nested randomized design with 2 factors as the first factor, the type of nitrogen source, while the second factor was the concentration of the nitrogen source in the first factor. The types of nitrogen sources used as the first factor were tofu industrial wastewater, green bean sprouts and Azolla microphylla, while the second factor was the concentration of nitrogen sources consisting of 4 levels, namely 0.5%, 1%, 1.5% and 2%. The parameters observed in this study were thickness of nata de coco, weight of nata de coco, crude fiber of nata de coco, number of Acetobacter xylinum cells in the nata de coco layer. The results showed that organic nitrogen sources (tofu, sprouts and Azolla microphylla liquid waste can be an alternative substitute for inorganic nitrogen sources (urea, ZA and ammonium sulfate) which have been commonly used in making nata. The highest quality nata de coco is produced from the treatment of organic nitrogen sources. sprouts with a concentration of 1.5% with a thickness of 2.83 cm, a weight of 279.33 grams, a crude fiber content of 4.14% and the number of Acetobacter xylinum cells in the cellulose layer 0.4 x 107 cells / ml.

Artificial Intelligence as a Combinatorial Optimization Strategy for Cellulase Production by Trichoderma stromaticum AM7 Using Peach-Palm Waste Under Solid-State Fermentation

The use of agro-industrial waste as substrate to produce enzymes has been widely studied in order to adjust the high productions of these biocatalysts with a reduction of the final cost in an ecologically correct process in the industry. This is the first work to use peach-palm (Bactris gasipaes Kunth.) waste for the production of carboxymethylcellulases (CMCase) by the Trichoderma stromaticum AM7 under solid-state fermentation (SSF) using the artificial neural network and genetic algorithm (ANN-GA) to optimize the cellulase production. ANN-AG was used to determine the optimal influence of nitrogen source concentration (2.46%), time (12 days), and temperature (26 °C) on the cellulase production with 98% of efficiency for algorithm prediction of endoglucanase activity. The predicted and experimental values of the CMCase activity in U/g of dry initial substrate (gds) were 122.9 and 120.0, respectively. After all optimization processes, the variation of these parameters allowed a final increase of 31.58-fold when compared to the initial fermentation. Moreover, the treatment of peach-palm waste with T. stromaticum AM7 endoglucanase had an effect on the degradation of the fibers analyzed by scanning electron microscopy and the saccharification of the waste by releasing reducing sugar (807.80 mg/g) for 8 h of incubation. These results are very promising to waste valorization and the biotechnological and industrial applications of cellulase of the T. stromaticum AM7 to food processes and biofuel production.

Statistical optimization of L-asparaginase production by Cladosporium tenuissimum

Background L-asparaginase produced by plant and bacteria can be used in the pharmaceutical and food industry. Unlike the bacterial counterparts, fungal L-asparaginase has more stability, more activity, and less adverse effects. Central composite design (CCD) was used to optimize temperature, pH, incubation time, and carbon-to-nitrogen ratio for L-asparaginase production by Cladosporium tenuissimum via submerged fermentation. CCD reduces the number of tests and time for optimization. Objective To optimize the culture conditions, such as temperature, pH, production time, and the ratio between concentration of carbon and nitrogen sources, for the production of L-asparaginase by isolated C. tenuissimum via submerged fermentation. Materials and methods Primarily, four significant parameters (temperature, pH, incubation period, and carbon-to-nitrogen ratio) were identified that affect the production process of L-asparaginase via submerged fermentation using the modified Czapek Dox medium. CCD was used to optimize the selected parameters concurrently, and their results were compared. Results and conclusions The highest L-asparaginase enzyme activity obtained was 2.6471 U/ml at 37°C, pH 6.2, incubation time 72 h, and 2 : 1 carbon-to-nitrogen ratio. The P value of interaction between every two factors was only significant for the interaction between temperature and incubation period (P

Adverse effects of nitrogenous compounds on nitrogen-fixing cyanobacterium Anabaena solitaria Klebahn

The nitrogen-fixing heterocystous cyanobacterium Anabaena solitaria was tested for its response to different concentrations of nitrogen sources, namely nitrate and ammonia. To compare both the effect of concentration and type of nitrogen source, gradual concentrations were prepared for both ammonia and nitrate. The results showed concentration was significantly important on the frequency of heterocyst formation where highest nitrogen compounds concentrations were inhibitory for heterocyst formation. On the other hand, the effect of the type of nitrogenous compounds tested was insignificant which only proves that they are equally usable by cyanobacteria which will use them instead of transforming one of its cells to heterocyst thus not performing nitrogen fixation. Results also revealed the massive growth of heterotrophic bacteria in presence of nitrogenous compounds. This indicates that the presence of nitrogenous compounds in fields in which nitrogen-fixing cyanobacteria are to be used as biofertilizers can be inhibitory for nitrogen fixation and stimulatory for heterotrophic bacterial growth which could be pathogenic and harmful to plants. The use of more nitrogen-fixing cyanobacteria with the minimum amount of nitrogenous compounds is recommended.

The preliminary optimization of culture components for improving antifungal production by a wild-type soil bacteria Bacillus subtilis

Antifungal compounds are produced by Bacillus species under various growth conditions. While optimizing the antifungal production by using the one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches mannose and malt extract were identified as the most suitable carbon and nitrogen sources respectively. The RSM was applied to determine the optimum conditions of the three parameters such as pH, carbon and nitrogen sources for improved production. Optimum concentrations of carbon and nitrogen sources were 0.3% and 0.6% respectively with optimum media pH of 7.0 which showed optimum value of 40 AU/ml of antifungal compound against the Candida albicans SC5314 used as an indicator strain. In the present study, the F-value was determined as 0.0034 to imply that the model is significant. The goodness of the fit of the model was tested using coefficient of determination, R2 value, that tantamounts to 0.8562. The identification of antifungal compounds with their molecular masses was accomplished by MALDI-TOF mass spectrometry after n- butanol extraction. The present study thus has provided a platform to upgrade the yield of antifungal compounds which have got immense clinical potential to tread Candidosis.

Effect of Type of Nitrogen Sources and Concentration on Protease Production: Fish Waste Hydrolysate as a Potential Low Cost Source

Fish waste hydrolysate is obtained from hydrolysis process of a fishery industry waste. It can be a good substrate source for the production of protease via a fermentation process. Protease covers above than 50% of the global industrial enzymes market and is regarded as an enzyme which is widely used in many applications. This research aims to determine the effect of the type of nitrogen sources and nitrogen source concentration on protease production from the fish waste hydrolysate. The experiments were done using one factor at a time (OFAT) of type of nitrogen sources and nitrogen source concentration in submerged fermentation (SmF) of 10% (v/v) Bacillus cereus (ATCC 10876). In the first stage, the variation of type of 1% (w/v) nitrogen sources such as fish waste hydrolysate, beef extracts, yeast extracts, tryptone, peptone and skim milk powder that mixed with the basal media were compared to evaluate the highest protease production. Then, the concentration of fish waste hydrolysate was varied from 1% to 3% (w/v) to analyse the production trend of protease. The protease activity and total protein content were then analysed by protease assay using tyrosine as a standard and Bradford method, respectively. Upon the observation, 1% (w/v) nitrogen sources on protease production revealed that the fish waste hydrolysates and beef extracts were capable to produce a high amount of protease (23.659 ± 0.38 U/mL and 28.7631 ± 0.59 U/mL, respectively). Among the concentration tested, 3% (w/v) of fish waste hydrolysate was found to be the highest protease production (190.85 ± 0.38 U/mL). Therefore, the fish waste hydrolysate has a potential as a low-cost source for protease production.

Nutrient removal by Arthrospira platensis cyanobacteria in cassava processing wastewater

Industrial processing of cassava and other starch-containing tubercles generates high amounts of nutrient-rich wastewater that cannot be directly disposed in rivers or lakes. This work evaluates the bioremediation of cassava processing wastewater using the cyanobacteria Arthrospira platensis, focusing on removing nitrogen and phosphorous sources. An experimental design was carried out comprising treatments consisting in the feed of 0.0–2.0 mL/day of cassava processing wastewater per liter of culture in a feed-batch operation. The experiments were carried out at pH 11.0 and 23 °C. The effects of cassava processing wastewater were evaluated on the number of trichomes, growth rate, number of divisions per day, generation time, and nutrient consumption by the cyanobacteria. Arthrospira platensis bioremediation had improved performance at 1.5 mLwastewater/day/Lculture of cassava processing wastewater regarding the growth of colonies and removing nutrients from the wastewater. The treatment at low feed rates resulted in total removal of ammonia and nitrites, and partial removal of nitrates and phosphates. The result indicates that Arthrospira platensis could be applied in bioremediation of agroindustry wastewaters that contain high concentrations of nitrogen sources, especially ammonia and nitrites. However, industrial treatment should be carried out in stabilization ponds due to the low required feed rate for optimal removal of nutrients.