Faculty of Science, School of Biosciences, The University of Nottingham Malaysia Campus, Semenyih, Selangor Darul Ehsan, Malaysia.
J Appl Microbiol. 2012 Oct;113(4):925-39. doi: 10.1111/j.1365-2672.2012.05398.x. Epub 2012 Aug 10.
To investigate the antifungal activity of conventional chitosan and chitosan-loaded nanoemulsions against anthracnose caused by Colletotrichum spp. isolated from different tropical fruits.
In vitro results illustrated that conventional chitosan onwards 1·5% concentration inhibited radial mycelial growth, conidial germination, sporulation and dry weight of mycelia for Colletotrichum musae (Berk. & Curt) Arx. isolated from banana, Colletotrichum gloeosporioides (Penz.) Penz and Sacc. isolated from papaya and dragon fruits. For further investigations, chitosan-loaded nanoemulsions were prepared, and chitosan at 2·0% concentration with 200 nm droplet size gave the best results in terms of all the in vitro parameters tested for C. musae and at the same concentration with 600 nm droplet size for both the isolates of C. gloeosporioides. However, the results obtained at 2·0% chitosan concentration with different droplet sizes were nonsignificantly different with 1·0 and 1·5% concentrations. Therefore, for in vivo studies, only 1·0% chitosan with different droplet sizes was used. In terms of fungicidal effects and maintaining postharvest quality of banana, papaya and dragon fruits, chitosan at 1·0% concentration with a droplet size of 200 nm in banana and 600 nm in papaya and dragon fruits showed the best results in delaying the onset of anthracnose and maintaining quality of all the fruits for up to 28 days of cold storage.
Chitosan used in a conventional form showed good results but not as effective as in the form of nanoemulsions.
The results of this study suggest that instead of applying chitosan in a conventional form, chitosan in the form of nanoemulsions could be more effective as a biofungicide for controlling anthracnose of fresh fruits. Moreover, it could be cost-effective as the amount of chemical used is reduced when applied in the form of nanoemulsions.
研究常规壳聚糖和壳聚糖负载纳米乳液对分离自不同热带水果炭疽病的炭疽菌的抗真菌活性。
体外结果表明，常规壳聚糖浓度为 1.5%及以上时，可抑制香蕉炭疽病菌（Colletotrichum musae (Berk. & Curt) Arx.）、番木瓜炭疽病菌（Colletotrichum gloeosporioides (Penz.) Penz and Sacc.）的径向菌丝生长、孢子萌发、产孢和菌丝干重。为了进一步研究，制备了壳聚糖负载纳米乳液，壳聚糖浓度为 2.0%、粒径为 200nm 时对 C. musae 的所有体外参数的结果最佳，而在相同浓度下粒径为 600nm 时对两种 C. gloeosporioides 菌株的结果最佳。然而，在 2.0%壳聚糖浓度下不同粒径大小的结果与 1.0%和 1.5%浓度的结果没有显著差异。因此，在体内研究中，仅使用了不同粒径大小的 1.0%壳聚糖。就香蕉、番木瓜和火龙果炭疽病的杀菌效果和保持采后品质而言，浓度为 1.0%、粒径为 200nm 的壳聚糖在香蕉中、粒径为 600nm 的壳聚糖在番木瓜和火龙果中效果最佳，可延迟炭疽病的发生，并在冷藏 28 天内保持所有水果的品质。
常规形式的壳聚糖表现出良好的效果，但不如纳米乳液形式有效。
本研究结果表明，壳聚糖以纳米乳液的形式应用比以常规形式更有效，可作为控制新鲜水果炭疽病的生物杀菌剂。此外，由于以纳米乳液的形式应用时减少了化学物质的使用量，因此成本效益更高。
