Abstract Background Pineapple plant ( Ananas comosus ) is one of the largest productions in Asia and its increasing production has generated a huge amount of pineapple wastes. Pineapple plant stem is made up of high concentration of starch which can potentially be converted into value-added products, including amino acids. Due to the increasing demand in animal feed grade amino acids, especially for methionine and lysine, the utilisation of cheap and renewable source is deemed to be an essential approach. This study aimed to produce amino acids from pineapple plant stem hydrolysates through microbial fermentation by Pediococcus acidilactici Kp10. Dextrozyme was used for hydrolysis of starch and Celluclast 1.5 L for saccharification of cellulosic materials in pineapple plant stem. Results The hydrolysates obtained were used in the fermentation to produce methionine and lysine. Pineapple plant stem showed high starch content of 77.78%. Lignocellulosic composition of pineapple plant stem consisted of 46.15% hemicellulose, 31.86% cellulose, and 18.60% lignin. Saccharification of alkaline-treated pineapple plant stem gave lower reducing sugars of 13.28 g/L as compared to untreated, where 18.56 g/L reducing sugars obtained. Therefore, the untreated pineapple plant stem was selected for further process. Starch hydrolysis produced 57.57 g/L reducing sugar (100% hydrolysis yield) and saccharification of cellulosic materials produced 24.67 g/L reducing sugars (56.93% hydrolysis yield). The starch-based and cellulosic-based of pineapple plant stem were subjected as carbon source in methionine and lysine production by P. acidilactici Kp10. Conclusions In conclusion, higher methionine and lysine production were produced from starch-based hydrolysis (40.25 mg/L and 0.97 g/L, respectively) as compared to cellulosic-based saccharification (37.31 mg/L and 0.84 g/L, respectively) of pineapple plant stem. Graphical Abstract
An extracellular α -amylase from the obligate halophilic Aspergillus penicillioides TISTR3639 strain was produced and enriched to apparent homogeneity by ammonium sulfate precipitation and Sephadex G100 gel filtration column chromatography. The mass of the purified amylase was estimated to be 42 kDa by SDS-PAGE. With soluble starch as the substrate it had a specific activity of 118.42 U·mg −1 andVmaxandKmvalues of 1.05 µ mol·min −1 ·mg −1 and 5.41 mg·mL −1 , respectively. The enzyme was found to have certain polyextremophilic characteristics, with an optimum activity at pH 9, 80°C, and 300 g·L −1 NaCl. The addition of CaCl 2 at 2 mM was found to slightly enhance the amylase activity, while ZnCl 2 , FeCl 2 , or EDTA at 2 mM was strongly or moderately inhibitory, respectively, suggesting the requirement for a (non-Fe 2+ or Zn 2+ ) divalent cation. The enzyme retained more than 80% of its activity when incubated with three different laundry detergents and had a better performance compared to a commercial amylase and three detergents in the presence of increasing NaCl concentrations up to 300 g·L −1 . Accordingly, it has a good potential for use as an α -amylase in a low water activity (high salt concentration) and at high pH and temperatures.
Cellulase activities assay for the enzyme produced from a filamentous fungus Trichoderma reesei strain QM9414 and Rut C-30 were performed. Reducing sugar released from cellulase hydrolysis was detected by dinitrosalicylic acid (DNS) method. The color developed from DNS was then measured by Digital Image Processing (DIP) technique in normal scale comparing the conventional spectrophotometric assay to the new DIP technique. Both spectrophotometric assay and DIP technique showed similar average cellulase activities with no statistically difference (P>0.05) among the 2 methods in normal scale. The cellulase activities of T. reesei QM9414 and Rut C-30 were measured, using mini-scale (5 times reduced) of DNS method comparing spectrophotometric assay to the DIP technique. The mini-scale of spectrophotometric assay and the DIP technique also displayed no difference of cellulase activities at confidence interval 95%. This study showed that the cellulase activity determination in the mini-scale by the DIP technique could rapidly be used for the determination with convenience and accuracy.
The effect of Avid® on the induction of synnema-like structure of Aspergillus flavus (61 strains) grown on various types of agar media was investigated. Other related species of Aspergillus within the section Flavi, A. parasiticus (14 strains), A. nomius (14 strains), A. psuedotamarii (2 strains),A. tamarii (20 strains) and A. oryzae (5 strains), were also evaluated for comparison. When Avid®was added into five different solid media (Czapek, V8, Aspergillus flavus and A. parasiticus, corn meal and potato dextrose agar) at 0.004% (v/v), only the A. flavus strains (all 61 tested) were able to produce synnema-like structures, and only in the Czapek agar medium containing Avid®. The effect of carbon (sucrose, glucose and starch) and nitrogen (NaNO3, urea and peptone) sources in Czapek medium containing Avid® on the induction of a synnema-like structure was also determined, with synnema-like structure induction being found in all three carbon sources but only in NaNO3 as the nitrogen source. All the three of the inert solvents in Avid® (mineral oil, butylated hydroxytoluene and n-methylpyrrolidone) did not induce synnema-like structure formation, indicating that abamectin, an active ingredient of Avid® together with NaNO3 likely play important roles in the induction of synnema-like structure of A. flavus. Key words: Aspergillus flavus, Avid®, synnema-like structure.
Infection is one of the health problems and a disease that mainly causes death. Malaria is a parasitic infection that is transmitted through the Anopheles sp. The female then causes infection and besides malaria, other contaminants that caused infection are bacteria such as Escherichia coli and Staphylococcus aureus. This study aims to determine the antioxidant, antimicrobial, and antiplasmodial activity of Sonchus arvensis L. ethyl acetate fractions. In vitro antiplasmodial activity was carried out by Rieckman methods against Plasmodium falciparum strain 3D7. In vitro antioxidant activity was conducted by Prieto method against (1,1-diphenyl-2-picrylhydrazyl (DPPH). Then antimicrobial activity was performed using well diffusion method against Escherichia coli and Staphylococcus aureus. Maceration of S. arvensis L. dried leaves used n-hexane and ethyl acetate successively. Then the ethyl acetate extract was fractionated by vacuum column chromatography, using n-hexane and ethyl acetate as mobile phases. There are five fraction groups based on thin-layer chromatography (TLC) analysis. The IC50 of antioxidant and antiplasmodial activity showed that fraction IV was the lowest value and categorized as active for antioxidant (IC50=22.56 μg/mL), for antiplasmodial (IC50=12.07 μg/mL). Fraction IV also had antimicrobial activity, with diameter of inhibition zone (DIZ) of 19.22 mm against Escherichia coli and 17.167 mm against Staphylococcus aureus.
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