Over the past decade, reckless usage of synthetic pesticides and fertilizers in agriculture has made the environment and human health progressively vulnerable. This setting leads to the pursuit of other environmentally friendly interventions. Amongst the suggested solutions, the use of chitin and chitosan came about, whether alone or in combination with endophytic bacterial strains. In the framework of this research, we reported an assortment of studies on the physico-chemical properties and potential applications in the agricultural field of two biopolymers extracted from shrimp shells (chitin and chitosan), in addition to their uses as biofertilizers and biostimulators in combination with bacterial strains of the genus Bacillus sp. (having biochemical and enzymatic properties).

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Background: Chitin and chitosan are natural products extracted from shrimp shells. They are non-toxic, biocompatible and biodegradable which favors many applications in agricultural domain. Moreover, chitin and chitosan are known as stimulators of photosynthetic rates and enhance pants growth through minerals contains (C, O, N ….). In the present study, these co-products are evaluated for their ability to stimulate the germination and growth of Lycopersicon esculentum L., Capsicum annuum L. and Solanum melongena L. Methods: The experiments were conducted at Ibn Tofail University-Kenitra, between July 2016 to January 2018. The experiments are carried out by using a germination test for the three seeds. On the other hand, the in vivo test is used to determine the effect of the biopolymers on plant growth (length, fresh and dry weights of aerial and root parts, number and weight of the obtained fruits). Result: In vitro studies reveal a promoter action of chitosan and the mixture chitin-chitosan on increasing seed germination percentage by 16%, 34% and 22%. Thus, at both 25, 50 and 100 mg/l of chitin or chitosan, increase vigor index, shoot length and root is obtained. In vivo, the effect of chitin and chitosan is limited to stimulation of the lengths, fresh and dry weights of plants. However, a highly significant increase in the number and weight of the fruits is marked by the weekly soil amendment by the chitin-chitosan mixture at 25 mg/l and 100 mg/l.

The present work reports the synthesis of pure hydroxyapatite and HAp supported Ag3PO4 (Ag3PO4/HAp composites) with varying amounts of silver ions Ag+ with a facile in-situ ion exchange method. XRD results of Ag3PO4/HAp composite reveal the peaks characteristic of pure HAp with additional peaks of silver ions which suggest the deposit of silver particles on the support surface (HAp). The nano-composites Ag3PO4/HAp samples show good adsorption and improved photocatalytic activities in methylene blue MB degradation (more than 70%). Antibacterial study of Ag3PO4/HAp nano-composites showed that the HAp dried at 90°C possesses some antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. Also, compared to HAp sample, deposition of Ag3PO4 nanoparticles on HAp surface improves the antibacterial performance of the composites.

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