Optimization of xylanase production by filamentous fungi in solid state fermentation and scale-up to horizontal tube bioreactor

Five microorganisms, namely Aspergillus niger CECT 2700, A. niger CECT 2915, A. niger CECT 2088, Aspergillus terreus CECT 2808, and Rhizopus stolonifer CECT 2344, were grown on corncob to produce cell wall polysaccharide-degrading enzymes, mainly xylanases, by solid-state fermentation (SSF). A. niger CECT 2700 produced the highest amount of xylanases of 504±7 U/g dry corncob (dcc) after 3 days of fermentation. The optimization of the culture broth (5.0 g/L NaNO3, 1.3 g/L (NH4)2SO4, 4.5 g/L KH2PO4, and 3 g/L yeast extract) and operational conditions (5 g of bed loading, using an initial substrate to moistening medium of 1:3.6 (w/v)) allowed increasing the predicted maximal xylanase activity up to 2,452.7 U/g dcc. However, different pretreatments of materials, including destarching, autoclaving, microwave, and alkaline treatments, were detrimental. Finally, the process was successfully established in a laboratory-scale horizontal tube biore- actor, achieving the highest xylanase activity (2,926 U/g dcc) at a flow rate of 0.2 L/min. The result showed an overall 5.8-fold increase in xylanase activity after optimization of culture media, operational conditions, and scale-up.We are grateful to the Spanish Ministry of Science and Innovation for the financial support of this work (project CTQ2011-28967), which has partial financial support from the FEDER funds of the European Union; to the Leonardo da Vinci Programme for founding the stay of Felisbela Oliveira in Vigo University; to MAEC-AECID (Spanish Government) for the financial support for Perez-Bibbins, B. and to Spanish Ministry of Education, Culture and Sports for Perez-Rodriguez's FPU; and to Solla E. and Mendez J. (CACTI-University of Vigo) for their excellent technical assistance in microscopy

Characterization Of Beta-Galactosidase From Alternaria Alternata On Solid-State Cultivation

The effects of orange peel, lemon peel, apple peel, wheat-bran and watermelon peel on beta-galactosidase production from Alternaria alternata were studied. Beta-galactosidase (EC-3.2.1.23) was produced best by solid-state fermentation of A. alternata on wheat bran. The effects of pH and incubation temperature were studied. The highest enzyme activity was obtained at 50 degrees C and pH 5.0. The enzyme was relatively stable in the pH range 3.0-5.0 and between 20 degrees-50 degrees C. The enzyme maintained 85% of its activity at 20 degrees-30 degrees C and 70% at 50 degrees C. Activity was more than 92% between pH 3.0-5.0 and 42% in 40 min and 50% in 30 min at 60 degrees C. In addition, glucose did not have an inhibitory effect, and galactose had only a slight inhibitory effect.Wo

Xylanase production from Trichoderma harzianum 1073 D3 with alternative carbon and nitrogen sources

The effect of some natural wastes (orange pomace, orange peel, lemon pomace, lemon peel, apple pomace, pear peel, banana peel, melon peel and hazelnut shell) on the production of xylanase from Trichoderma harzianum 1073 D3 has been studied and maximum activity has been observed on melon peel (26.5 U/mg of protein) followed by apple pomace and hazelnut shell. Also, molasses could be used as an additional carbon source as it decreased the production time approximately by 50%. Finally, potential alternatives of organic nitrogen source (cotton leaf and soybean residue wastes) were analyzed and it was concluded that peptone could be replaced with these residues especially when economics of the process is the major objective

Production of lactase by Trichoderma sp.

In order to find an alternative fungal source, 13 different fungi (Aspergillus, Trichoderma, Penicillium, Rhizopus and Fusarium sp.) were cultured in lactase production medium at 30 degreesC and 150 rpm for 6 days. Experimental results showed that Trichoderma viride ATCC 32098 has maximum lactase specific activity, followed by Trichoderma harzianum 1073 D3. In addition, the studies of stability were carried out in the pH range of 3.0-7.5 at the temperature between 20 and 70 degreesC. It was observed that the activity of lactase produced from T. viride ATCC 32098 was above 90 % in the pH range of 3.0-7.5 at the temperature between 20 and 60 degreesC, and even 66 % at 70 degreesC. It was concluded that Trichoderma sp., especially T. viride ATCC 32098, could be used as an alternative for the production of lactase in industrial scale

Determination of some physiological factors affecting xylanase production from Trichoderma harzianum 1073 D3

In this study, different Trichoderma strains were tested and Trichoderma harzianum 1073 D3 was found to be the most potent xylanase producer. Then some cultural parameters, namely, incubation time, substrate concentration, initial culture pH and temperature were optimized in order to increase xylanase production from Trichoderma harzianum 1073 D3. The optimum incubation time was found to be 13 days. It was concluded that 1% xylan concentration is suitable for high xylanase production rate. The optimum temperature and pH were found to be 30degreesC and 7, respectively. Also, it was determined that agitation during growth was suitable for efficient production

Comparison of live and dead biomass of fungi on decolorization of methyl orange

Decolorization of methyl orange with live and autoclaved biomass fungi were studied. Sixteen different fungi including Fusarium, Trichoderma, Humicola, Aspergillus, Penicillium, Paecilomyces, Alternaria and Beauveria were evaluated. The highest decolorization activity was observed with Fusarium acuminatum and Humicola fuscoatra. Decolorization efficiencies of live and autoclaved biomasses were compared. In addition, spores of eight fungi showing high decolorization efficiency were inoculated fordecolorization ability. The most successful fungi were Penicillium sp. and Fusarium sp. For adsorption studies, methyl orange decolorization with live and autoclaved biomasses were found most suitable with malt extract compared to yeast extract peptone medium

Biodegradation of petroleum by Klebsiella pneumoniae isolated from drilling fluid

The removal of petroleum and petroleum-based products from the environment is of great importance. The objectives of this study were to investigate the most suitable physiological conditions and the effects of additional carbon, nitrogen and surfactant sources on petroleum biodegradation by Klebsiella pneumoniae ATCC13883 isolated from drilling fluid and to evaluate petroleum biodegradation with detailed hydrocarbon analysis by GC-MS. The results indicated that the highest biodegradation rate of 66.5% for K. pneumoniae was obtained under the conditions of pH 7, petroleum concentration 1% (v/v) and 7-day incubation at 150rpm and 25 degrees C, proving to be the most effective physical conditions for petroleum biodegradation in this present study. Additional sources such as Triton X: 100, glucose and yeast extract significantly enhanced the petroleum biodegradation of K. pneumoniae to 68, 71 and 72.5%, respectively. In the last stage of this study, biodegradation rates were above 90% for hydrocarbons ranging from C-10 and C-20, above 70% for hydrocarbons ranging from C-21 and C-22 and above 40% for hydrocarbons ranging from C-31 and C-32. In conclusion, oil field adapted K. pneumoniae could efficiently degrade short-, medium- and long-chain alkanes in petroleum and thus is a potential source for advanced petroleum treatment