Production of chitinolytic enzymes with Trichoderma longibrachiatum IMI 92027 in solid substrate fermentation

Thirty Trichoderma strains representing 15 species within the genus have been screened for extracellular production of chitinolytic enzymes in solid substrate fermentation (SSF). T.longibrachiatum IMI 92027 (=ATCC 36838) gave the highest yield (5.0 IU/g dry matter of substrate) after 3 days of fermentation on wheat bran-crude chitin (9:1 mixture) medium. The optimum moisture content (66.7%), chitin content (20%), initial pH of the medium (2-5) and time course (5 d) of SSF were determined for strain IMI 92027. No significant effect of different N and P additives was found on the chitinase yield in wheat bran-chitin mixture medium. Cellulase, xylanase, alpha-amylase and beta-xylosidase activities were also detected. The pH and temperature optima of chitinase complex of T.longibrachiatum IMI 92027 was found to be at 4.5 and 55 ℃, respectively. The enzyme totally lost its activity at 70 ℃ in 5 min in the absence of the substrate but retained about 15% of its initial activity even at 70 ℃ after incubation of 60 min in the presence of SSF solids (residual substrate and fungal mycelium). Purification of protein extract from the SSF material revealed high chitinolytic activities between pI 5.9.-4.8 where N-acetyl-β-D-hexosaminidase and chitinase peaks have been found in the same pI range. Chitinase peaks could be described at least at four pI values: pI 5.9; 5.6; 5.3 and 4.8 while at least four main N-acetyl-β-D-hexosaminidase peaks could be separated at pI 6.0 and 5.1 and at more basic isoelectric points of 7.2 and 8.0. Two chitinases with 43.5 kDa and 30 kDa were purified at acidic isoelectric point.

Production of chitinases with Trichoderma harzianum isolates using solid substrate fermentation

Over forty Trichoderma harzianum isolates have been screened in solid substrate fermentation (SSF) for chitinase production. Strains were isolated from Asian soil and tree bark samples. Identification was performed in Canada and Austria by classical and molecular taxonomical methods. Four SSF media were used for the screening. They contained wheat bran, crude chitin from crab shells (SIGMA) and different salt solutions for wetting of the substrate. In a five day fermentation at 30°C the best chitinase producers were T. harzianum TUB F-691, TUB F-693, TUB F-699, TUB F-700, TUB F-927, TUB F-947 and TUB F-972 isolates (TUB = Technical University of Budapest culture collection) . The best producers yielded between 3.5-5.5 International Unit/g dry matter (DM) chitinase. T. harzianum TUB F-947 was selected for further optimization. This strain was isolated from a soil of Thailand. The optimum moisture content (67%), optimal alternative substrate-carrier for SSF (wheat straw) and chitin content of the substrate (30%) were determined. Temperature and pH optima of chitinase produced by T. harzianum TUB F-947 were found to be at 50°C and 5.0, respectively. The enzyme complex was thermally not stable at 50 ℃. Medium optimization experiments to enhance the chitinase production using statistical methods also have been performed.

Engineering microalgae as the next-generation food

Globally,microalgae are gaining attention due to their high nutritional value and broad application in the pharmaceutical,nutraceutical,food,cosmetics,bio-fertilizer,and biofuel industries.Microalgal-based foods have been shown a positive impact on human health by acting as antioxidants,antimicrobials,anti-inflammatory agents,and antiviral agents.Scale-up,production cost,and safety issues are the significant challenges in microalgae product commercialization.However,various techniques have been developed to overcome these challenges and to produce microalgae bio-products in a high amount and make them safe for human and animals use.Recently,multiple techniques such as metabolic and genetic engineering have emerged to overcome these limitations.The present review focused on the application of these engineering tools to improve biomass yield and nutrient quality in microalgae.However,these tools are proved to be very effective in enhancing the nutrients in microalgae.Limited success has been achieved to improve the quality at the industrial level.

Solid-state fermentation technology and innovation for the production of agricultural and animal feed bioproducts

It has now passed more than forty years since solid-state fermentation(SSF)research developments have gained importance for the scientific community.After so many years,numerous processes and equipment for SSF were studied and designed focusing on the production of different commercially relevant bioproducts such as enzymes,fermented food,such as Chinese daqu and koji,organic acids,pigments,phenolic compounds,aromas,biosorbents and so many others.However,no review paper has been focused yet specifically on agricultural and animal feed bioproducts obtained through SSF techniques.This review comprises the description of agricultural sub-products that have been employed in most important developed pro-cesses concerning the production of animal feed products and agricultural products such as spores,probiotics,biofungicides,bioinsecticides and other biopesticides,biofertilizers and plant growth hormones.Major designed SSF bioreactors are also described and the most important related cases of successful employment of the technique are reported.Finally,a summary of patents and innovations regarding SSF products and processes in this area is presented,showing that the main involved countries are China,South Korea,India and the USA.It is clear that the interest in this theme is increasing and that scientific and technological developments are still needed.

Ethanol production by a filamentous fungal strain Byssochlamys fulva AM130 under alternating aerobic and oxygen-limited conditions

Byssochlamys fulva AM130,a novel strain of filamentous fungus,could produce ethanol from glucose,xylose,and alkali pretreated rice straw(PRS),while the efficiencies were very low with PRS.Ethanol production of 11.84 g/L was attained by the fungus when grown in glucose,indicating that the limitations while growing on PRS were related to low hydrolytic efficiency.Enzyme profiling of the fungus showed 365 IU/ml of beta-glucosidase and 89 IU/ml of xylanase activity,while endoglucanase and filter paper activity were negligible,which accounts for the low hydrolytic efficiency.The fungus could survive for extended periods under oxygen-limited conditions and produce ethanol.The fungal mycelia could also be used for repeated cycles of anaerobic fermentation,wherein the ethanol yield improved with each consecutive cycle.

Glycerol waste to value added products and its potential applications

The rapid industrial and economic development runs on fossil fuel and other energy sources.Limited oil reserves,environmental issues,and high transportation costs lead towards carbon unbiased renewable and sustainable fuel.Compared to other carbon-based fuels,biodiesel is attracted worldwide as a biofuel for the reduction of global dependence on fossil fuels and the greenhouse effect.During biodiesel production,approximately 10%of glycerol is formed in the transesterification process in a biodiesel plant.The ditching of crude glycerol is important as it contains salt,free fatty acids,and methanol that cause contamination of soil and creates environmental challenges for researchers.However,the excessive cost of crude glycerol refining and market capacity encourage the biodiesel industries for developing a new idea for utilising and produced extra sources of income and treat biodiesel waste.This review focuses on the significance of crude glycerol in the value-added utilisation and conversion to bioethanol by a fermentation process and describes the opportunities of glycerol in various applications.