Alternative methods for gibberellic acid production, recovery and formulation: A case study for product cost reduction

The aim of this work was to develop a new production, recovery and formulation process of gibberellic acid (GA₃). Low-cost byproducts - citrus pulp (CP) and soybean hulls (SH) - were employed as substrate for GA₃ production by Gibberella fujikuroi in semisolid fermentation. A CP/SH mixture (70%/30%) promoted high productivities both in bubble column reactor (1.66 mg L/h), and in stirred tank reactor (2.13 mg L/h). GA₃ production medium cost (US$ 6.70/m³) was reduced by 85% when compared to previously reported synthetic media (US$ 44.96/m³). It was described that GA₃ fermented extract has low stability, and that liquid and powder formulation of the fermented extract maintained the biomolecule activity over 6 months. Alginate and alginate/kefiran beads containing GA₃ showed encapsulation efficiency of 70% and 60%, respectively. This work supports good perspectives for GA₃ production using cheap substrates and simple formulation of clarified extract to favour its use in agricultural countries.

Nanotechnology-Based Delivery Systems: Highlights in Agricultural Applications

Due to the excessive use of chemical agents in agriculture, numerous problems have arisen, such as contamination of the environment, intoxication of non-target organisms and the development of resistance mechanisms by pests. To overcome these challenges, several sustainable technological approaches are being explored, and nanotechnology is one of them. This review aims to provide insights into the use of nanotechnology related to the agricultural sector. Articles were selected using the Web of Science and Science Direct databases; more than 50 manuscripts between 2015 and 2019 were reviewed. This review includes systems based on nanotechnology, in particular, for the sustained release of active ingredients for pest control, nutrition and plant growth. Nanoparticle-based formulations have great potential to increase agricultural productivity and reduce health and environmental impacts. However, there are certain technological challenges that must be addressed to allow the adoption of this technology for wider use in agri-food production

Current advances in gibberellic acid (GA3) production, patented technologies and potential applications

Gibberellic acid is a plant growth hormone that promotes cell expansion and division. Studies have aimed at optimizing and reducing production costs, which could make its application economically viable for different cultivars. Gibberellins consist of a large family of plant growth hormones discovered in the 1930s, which are synthesized via the terpenes route from the geranylgeranyl diphosphate and feature a basic structure formed by an ent-gibberellane tetracyclic skeleton. Among them, only four have biological activity, including gibberellic acid (GA₃), which acts as a natural plant growth regulator, especially for stem elongation, seed germination, and increased fruit size. It can be obtained from plants, fungi, and bacteria. There are also some reports about microalgae GA₃ producers. Fungi, especially Gibberella fujikuroi, are preferred for GA₃ production via submerged fermentation or solid-state fermentation. Many factors may affect its production, some of which are related to the control and scale-up of fermentation parameters. Different GA₃ products are available on the market. They can be found in liquid or solid formulations containing only GA₃ or a mixture of other biological active gibberellins, which can be applied on a wide variety of cultivars, including crops and fruits. However, the product's cost still limits its large and continuous application. New low-cost and efficient GA₃ production alternatives are surely welcome. This review deals with the latest scientific and technological advances on production, recovery, formulation, and applications of this important plant growth hormone.