Environmental and Spatial Modeling of Actinobacterial Growth Suitability in Egypt’s Nile Delta Agricultural Lands

Abstract

ACTINOBACTERIA are widely distributed across various habitats, including diverse soils and they play an important role in maintaining ecological balance and for producing bioactive metabolites. Therefore, the present study adopts an innovative approach to assess actinobacterial suitability growth along the eastern and southern part of Nile delta of Egypt using remote sensing and cartographic modeling. Multispectral Landsat imagery were utilized to retrieve land use/cover and environmental variables associated with actinobacterial growth. Multiple spectral indices as NDVI, SAVI, NDMI, MNDWI, NDBI, NDSI, ferrous minerals and LST were utilized as environmental input criteria for the model. Based on the optimal conditions of the environmental variables for actinobacterial growth, a novel cartographic model was developed to assess actinobacterial growth suitability along the eastern and southern part of Nile delta region. An observed fluctuation was reported in multiple spectral indices; 4ferrous minerals (0.342 to 1.113), NDBI (-0.491 to 0.054), NDSI (-0.639 to -0.142), NDMI (-0.054 to 0.491), SAVI (0.072 to 0.537), MNDWI (-0.398 to 0.089), NDVI (0.142 to 0.639) and temperature (33.06 to 39.94°C). The actinobacterial suitability model resulted in six levels. The highest two suitability levels; very high (0%) and high (27%), which represent the greatest potential for actinobacterial growth, were predominantly situated in the northern part of the study area, encompassing the governorates of Sharkiah, Qalyubia, Monofia, and the northern part of Ismalia. On the other hand, the lowest suitability level, (level six, 0.3%) was detected in the western and southern regions of the study area. The accuracy of the developed model was 87.2%, indicating a high level of reliability. Based on this percentage, the model can be confidently used to predict the potential presence of actinobacteria. This novel model showed a promising result and can be widely applied in mapping the potential areas for actinobacterial growth using environmental variables retrieved from Landsat imagery. Keywords: Soil Microorganisms, GIS Modeling, Spectral Indices, Environmental Suitability. 1. Introduction Actinobacteria are a diverse phylum of Gram-positive bacteria with high guanine-cytosine (G+C) content in their DNA, enabling them to thrive in various environments, including extreme habitats (Zhang et al., 2022). They play a vital role in ecological balance by decomposing organic matter, recycling nutrients, and enhancing soil fertility. Moreover, actinobacteria are prolific producers of bioactive secondary metabolites, such as antibiotics and enzymes, which are crucial for pharmaceutical and industrial applications. Their growth and distribution are influenced by environmental factors like soil composition, moisture content, temperature, and pH, directly impacting their metabolic activity and ecological functions (Elsayed et al., 2024 a,b). Ecologically, actinobacteria contribute to the decomposition of organic matter, nutrient cycling, and improvement of soil health. They help in solubilizing essential minerals, detoxifying pollutants, and promoting plant growth by suppressing harmful soil pathogens (Olanrewaju & Babalola, 2019). In addition, actinobacteria are dominant members of the soil microbiome, particularly in the rhizosphere, where their filamentous structures (mycelia) enhance their interaction with plant roots and other soil organisms. These mycelia can make up to 20% of the total bacterial biomass in root-associated soils (van der Meij et al., 2017). Because of these properties, they are valuable for applications in sustainable agriculture, environmental remediation, and the development of microbial-based solutions to improve crop productivity and soil resilience, especially under stress conditions like those found in arid and semi-arid environments.