Nano-encapsulation of naringinase produced by Trichoderma longibrachiatum ATCC18648 on thermally stable biopolymers for citrus juice debittering.

Characteristics of naringinase nano-encapsulated forms on different carrier materials (chitosan and alginate polymers) were investigated in this study. Screening of twelve fungal isolates for naringinase production indicated that Trichoderma longibrachiatum was the most promising. Grapefruit rind was used as a substrate containing naringin for naringinase production. TEM micrographs showed that chitosan nano-capsules were applied for the production of morphologically homogeneous enzymatic nano-particles with high enzyme encapsulation efficiency, small asymmetric sizes (from 15.09 to 27.07 nm with the mean of 21.8 nm) and rough surfaces compared to nano-encapsulated naringinase in alginate which showed nano-particle size (from 33.37 to 51.01 nm with the mean of 43.03 nm). It was revealed that the highest naringinase activity was found in case of chitosan nano-capsule naringinase compared to alginate nano-capsule one. Thermogram analysis (TGA) showed that the free enzyme loses about 92% of its weight at approximately 110°C, while the nano-encapsulated ones show more stability at higher temperatures. Conclusively, the nano-capsulation process improves the kinetics and operational stability so could be useful as a debittering agent for various thermal processing applications in citrus juices industries which makes the fruit juice more acceptable and cost-effective to the consumer.

Micro- and nano-capsulated fungal pectinase with outstanding capabilities of eliminating turbidity in freshly produced juice.

The present study aimed to compare the pectinase forms produced from Trichoderma viride-free, micro-capsule, and nano-capsule-in sodium alginate to analyze the pectin that causes the turbidity of orange juice. This was performed along with an estimation of viscosity, residual of pectin, and turbidity. The extracted and purified enzyme was 24.35-fold better than that of the crude enzyme. After application of free one, it loses most of the activity on low degrees of acidity and remains constant on the temperatures of pasteurization. Therefore, the tested enzyme was encapsulated by two different ways using the same polymer. The morphology of the three pectinase forms was obtained by transmission electron microscopy, and the micrographs clearly showed the pores on the surface of sodium alginate matrix after encapsulation. The size of the wall (sodium alginate) ranged from 3.24 to 3.76 µm diameter but was 3.15 µm for core of enzyme. Micro-capsuled and nano-capsuled pectinase can be used in the hydrolysis of pectic substances in orange juice with natural ways and maintaining the quality of final product. Consequently, the cost of juice clarifying can be reduced due to reusing the enzyme several times.

A safe potential juice clarifying pectinase from Trichoderma viride EF-8 utilizing Egyptian onion skins.

The production of a notable, safe and highly active pectinase by the local fungal strain Trichoderma viride EF-8 utilizing the abundant pigmented Egyptian onion (Allium cepa L.) skins (6.5%, w/v) was achieved in 4 days submerged fermentation (SMF) cultures, at temperature and pH of 30 °C and 4.0, respectively. The indigenously produced pectinase was partially purified by 50% batch ethanol precipitation and its general properties were studied following the standard procedures. The lyophilized enzyme preparation was free of any ochra or aflatoxins. The optimum conditions for the partially purified enzyme form were 2 mg/mL and 1% (w/v) enzyme protein and substrate (citrus pectin) concentrations, reaction pH and temperature of 7.0 and 40 °C, respectively. The results presented the low cost onion skins waste as the major substrate for the fungal pectinase production and its subsequent use in perfect fruit (apple, lemon and orange) juices clarification with remarkable stability during and after this process, which certainly enhance fruit juices processing in the tropics.

Production of an endoinulinase from Aspergillus niger AUMC 9375, by solid state fermentation of agricultural wastes, with purification and characterization of the free and immobilized enzyme.

Two different substrates, sunflower (Helianthus annuus L.) tubers and lettuce (Lactuca sativa) roots, were tested. Using a mixture of both wastes resulted in higher production of endoinulinase than either waste alone. Also, ten fungal species grown on these substrates as inexpensive, carbon sources were screened for the best production of endoinulinase activities. Of these, Aspergillus niger AUMC 9375 was the most productive, when grown on the mixture using a 6:1 w/w ratio of sun flower: lettuce, and yielded the highest levels of inulinase at 50% moisture, 30°C, pH 5.0, with seven days of incubation, and with yeast extract as the best nitrogen source. Inulinase was purified to homogeneity by ion-exchange chromatography and gel-filtration giving a 51.11 fold purification. The mixture of sunflower tubers and lettuce roots has potential to be an effective and economical substrate for inulinase production. Inulinase was successfully immobilized with an immobilization yield of 71.28%. After incubation for 2 h at 60°C, the free enzyme activity decreased markedly to 10%, whereas that of the immobilized form decreased only to 87%. A reusability test demonstrated the durability of the immobilized inulinase for 10 cycles and in addition, that it could be stored for 32 days at 4°C. These results indicate that this inulinase, in the immobilized form, is a potential candidate for large-scale production of high purity fructose syrups.