Optimal Temperature For Production Research Articles

Scaling-Up of the Production of Biochar from Olive Tree Pruning for Agricultural Use: Evaluation of Biochar Characteristics and Phytotoxicity

Due to the large acreage of olive trees in the Mediterranean basin, the biochar from olive tree pruning may become an important resource as part of circular economy strategies. However, so far, there is not much knowledge on whether the same characteristics are repeated in biochar once production is up-scaled to an industrial level. Accordingly, this study aimed to scale up the production of olive tree pruning biochar with three reactors (semi-pilot, pilot and industrial) to ascertain the production parameters that determine the characteristics of the obtained biochar and its possible toxicity to use in agriculture or environmental applications. First, the production conditions in the semi-pilot reactor were optimised by testing three temperatures (400, 500 and 600 °C), with the result that 600 °C was the optimal production temperature because of a high carbon content (70.88%), moderate pH (8.1), good carbon sink (R50 > 0.5) and low contents of PAHs (<6 mg/kg) and heavy metals, resulting in a phytostimulanting effect for all the crops studied. Then, the production was upscaled, using 600 °C as pyrolysing temperature. At the industrial scale, accurate temperature control is essential because when temperatures above 650 °C were reached, the biochar showed a pH above 11, resulting in severe phytotoxicity. The longer retention time of the material in the industrial pyrolysers improved the carbon stability and, therefore, the biochar’s role as a carbon sink. Consequently, it was proven that it is possible to produce olive tree pruning biochar adequate for agriculture and environmental applications with large-scale equipment, and the two most important factors needing control are the temperature and retention time.

A Thermostable and Alkalitolerant Arabinofuranosidase by Streptomyces lividus

Aim: The study aimed at producing and purifying thermostable and alkalitolerant microbial arabinofuranosidase using local Palm Kernel Cake (PKC) as substrate.
 Study Design: This is an experimental design in which samples were collected thrice and subjected to laboratory analyses from which quantitative data were obtained and analysed.
 Place and Duration of Study: Ibadan, Nigeria, Five months.
 Methodology: Bacterial strains were isolated from degrading PKC by serial dilution and pour plate technique on formulated Modified Basal Salt Agar Medium and incubated at 50°C for enzyme activity screening. Plates were afterwards flooded with 1% congo red solution for visualization of hydrolysis zone. Its arabinofuranosidase activity was optimized in solid state fermentation in PKC. Production temperature, pH, moisture content, inoculum size and agitation were studied for optimization test. Optimal production temperature and pH for arabinofuranosidase by isolate was 45°C and pH 9. Produced arabinofuranosidase was purified to apparent homogeneity with ammonium sulphate precipitation, dialysis and column chromatography techniques. Stability of arabinofuranofuranosidase obtained to temperature, pH, substrate concentration and some ions was determined as well as its molecular weight using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).
 Results: Isolate with highest arabinofuranosidase activity was selected and identified as Streptomyces lividus. Purity level attained was 16.36 fold. Enzyme had a specific activity of 25.4 U/mg, and total enzyme activity of 13.2 U. Molecular weight of enzyme appeared as a band of 30 kDa. Purified arabinofuranosidase enzyme revealed optimum temperature and pH as 60oC and 9 respectively. Enzyme was stable over a broad pH range of 3-11, and temperature of 30-80oC. Residual activity after incubating for 1 hour at 70oC was 64%. Enzyme kinetics studies showed Km and Vmax values for P-nitrophenyl arabinofuranoside were 2.3mM and 0.7U/min respectively.
 Conclusion: Apart from Solid State Fermentation (SSF) of PKC being a potential fermentation technique for production of arabinofuranosidase by Streptomyces lividus, the enzyme was highly stable.

Determination of Optimal Temperature for Production of Quality Eri Silkworm Cocoon and Seed

Determination of Optimal Temperature for Production of Quality Eri Silkworm Cocoon and Seed

Thermal adaptability of Kluyveromyces marxianus in recombinant protein production

BackgroundKluyveromyces marxianus combines the ease of genetic manipulation and fermentation with the ability to efficiently secrete high molecular weight proteins, performing eukaryotic post-translational modifications. It is able to grow efficiently in a wide range of temperatures. The secretion performances were analyzed in the host K. marxianus L3 in the range between 5°C and 40°C by means of 3 different reporter proteins, since temperature appears a key parameter for production and secretion of recombinant proteins.ResultsThe recombinant strains were able to grow up to 40°C and, along the tested temperature interval (5-40°C), the specific growth rates (μ) were generally lower as compared to those of the untransformed strain. Biomass yields were slightly affected by temperature, with the highest values reached at 15°C and 30°C. The secretion of the endogenous β-fructofuranosidase, used as an internal control, was efficient in the range of the tested temperature, as evaluated by assaying the enzyme activity in the culture supernatants. The endogenous β-fructofuranosidase production was temperature dependent, with the highest yield at 30°C. The heterologous proteins HSA, GAA and Sod1p were all successfully produced and secreted between 5°C and 40°C, albeit each one presented a different optimal production temperature (15, 40, 5-30°C for HSA, GAA and Sod1p, respectively).ConclusionsK. marxianus L3 has been identified as a promising and flexible cell factory. In a sole host, the optimization of growth temperatures for the efficient secretion of each individual protein can be carried out over a wide range of temperatures.

Experimental Study on Impact of Production Process Parameters on Rubber Asphalt Performance

In order to better master the production process and the road performance of rubber asphalt, the paper studied the influence law of mixing method, mixing temperature, mixing time and rubber powder content on the performance of rubber asphalt. The results show that all the indexes except the viscosity of rubber asphalt has little change with different mixing methods, and the rubber asphalt has the best performance under the high-speed stirring molding method but the worst performance under the high-speed shearing molding method. Meanwhile, the performance of rubber asphalt change visibly with different mixing temperatures, on which the excessively high or low production temperature has negative significance, so the optimal production temperature would be recommended as 180~200°C. Furthermore, the mixing time and the rubber powder content are the two critical factors which may greatly affect the performance of rubber asphalt, followed by the mixing temperature and the mixing method.

Production of thaxtomin A by two species of Streptomyces causing potato scab.

A total of nine isolates of streptomycetes were isolated from scab lesions on potato tubers. Five of nine isolates were pathogenic on potato minitubers. Four of the pathogenic isolates produced thaxtomin A (ThxA) in infected tuber tissues. The lesion surface areas inducing ThxA were highest in treatment of the minitubers with an extract of OMB inoculated with S-66 and S-67, intermediate with that inoculated with S-64 and lowest with S-63. The pathogenic isolates were identified by gray aerial mycelia, melanin pigment productivity, the type of spore chain morphology and carbon utilization as S. scabies strains S-63, S-64 and S-68, and S. acidiscabies strains S-66 and S-67. Strains S-63 and S-64 produced 0.65 and 1.60 mg ThxA per L of OMB, respectively, strains S-66 and S-67 producing similar amounts, viz. 2.36 and 2.10 mg/L, respectively. The optimal temperature for production (by both species) was 28 degrees C. Production of ThxA by S. scabies strain S-64 and S. acidiscabies strain S-66 was suppressed at least 50-fold at 0.5 and 0.3% of glucose, respectively. Fructose enhanced the production by both species.

Regulation of scytophycin accumulation in cultures of Scytonema ocellatum. I. Physical factors

Scytonema ocellatum (Cyanobacteria or Cyanophyta) produces macrolide antibiotics of the scytophycin family that are antifungal, cytostatic agents and act by disrupting actin microfilaments. Scytophycin accumulation paralleled vegetative growth. Tolytoxin continued to accumulate throughout the growth cycle, whereas 6-hydroxy-7-O-methylscytophycin E (HMSE) and 19-O-demethylscytophycin C (DMSC) reached plateau levels prior to cessation of growth, suggesting a logical biosynthetic pathway of DMSC → ? → HMSE → tolytoxin. A rapid decrease in scytophycin content observed in newly inoculated cultures suggests that the scytophycins are continuously metabolized. The optimal temperature for production was 25°C. Continuous illumination at an intensity of at least 25 μml photons m−2 s−1 was required for maximum yield. Growth and metabolite production were optimal in the pH range of 8.0 to 8.5.

Fermentation of cassava peels for the production of cellulolytic enzymes

Cassava peels were used as a substrate for the production of cellulolytic enzymes. Under solid substrate fermentation conditions and a Rhizopus sp., thermostable cellulolytic enzymes were produced. Optimal production temperature and pH were 45°C and 5.6 respectively. Kinetic studies of the enzymes showed that the cellulase C1 activity was optimal at pH 5.0 and 50°C, whereas that of cellulase Cx was optimal at pH 7.0 and 60°C. The enzymes degraded ca 44% of sorghum grains in 6 h, thus suggesting a possible use in saccharification processes. The results also showed the possibility of re‐cycling cassava peels as a cheap substrate for the enzyme industry. and accepted 6 June 1989

Characterization of the motile hormogonia of Mastigocladus laminosus.

The cyanobacterium Mastigocladus laminosus produces motile hormogonia which move by gliding motility. These hormogonia were characterized in terms of their morphology, state of differentiation of the cells, optimal temperature for production and motility, minimal nutritional requirements to sustain motility, liberation of the hormogonium from its parental trichome, average surface velocity, and maximal concentration of agar through which the hormogonium may move. We found that an average hormogonium consisted of 13.6 cells of only the narrow-cell-type morphology. Gliding motility and the production of hormogonia were maximal at 45 degrees C. Agarose plus 0.20 mM Ca2+ was sufficient to sustain gliding motility. Hormogonia were liberated from the parental trichome by formation and lysis of a necridium. The average surface velocity of a hormogonium was 1.7 micron/s with a maximal velocity of 3 micron/s. Hormogonia were motile through 7% agar. Motile hormogonia leave a record of their passage in the form of easily visible tracks on the surface of solid media. Three types of tracks were observed: straight, sinusoidal, and circular. Normal, forward-directed motion involves screwlike rotation that describes a right-handed helix. However, observations are presented which suggest that rotational motion is not a prerequisite for gliding motility in this cyanobacterium.