Novel method to achieve crystallinity of calcite by Bacillus subtilis in coupled and non-coupled calcium-carbon sources

Héctor Ferral-Pérez,Marisela Aguirre-Ramírez,Aldo Izaguirre-Pompa,Mónica Galicia-García,Bonifacio Alvarado-Tenorio

doi:10.1186/s13568-020-01111-6

Héctor Ferral-Pérez, Marisela Aguirre-Ramírez + Show 3 more

Open Access

https://doi.org/10.1186/s13568-020-01111-6

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Journal: AMB Express	Publication Date: Sep 29, 2020
Citations: 10	License type: open-access

Affiliation: Universidad Autónoma de Ciudad Juárez

Abstract

Bacteria mineralization is a promising biotechnological approach to apply in biomaterials development. In this investigation, we demonstrate that Bacillus subtilis 168 induces and influences CaCO3 composites precipitation. Crystals were formed in calcium-carbon non-coupled (glycerol + CaCl2, GLY; or glucose + CaCl2, GLC) and coupled (calcium lactate, LAC; or calcium acetate, ACE) agar-sources, only maintaining the same Ca2+ concentration. The mineralized colonies showed variations in morphology, size, and crystallinity form properties. The crystals presented spherulitic growth in all conditions, and botryoidal shapes in GLC one. Birefringence and diffraction patterns confirmed that all biogenic carbonate crystals (BCC) were organized as calcite. The CaCO3 in BCC was organized as calcite, amorphous calcium carbon (ACC) and organic matter (OM) of biofilm; all of them with relative abundance related to bacteria growth condition. BCC-GLY presented greatest OM composition, while BCC-ACE highest CaCO3 content. Nucleation mechanism and OM content impacted in BCC crystallinity.

Highlights

Bacterial CaCO3 mineralization is a phenomenon that occurs in sediments, caves, hot springs, soils and even in monuments and buildings (Ciferri et al 2000; Rusznyák et al 2012; Páramo et al 2015)
Composites biomineralization After 9 days of incubation at 37o C, B. subtilis mineralized colonies were harvested from Petri dishes with nutrient agar supplemented with glycerol + CaCl2 (GLY), glucose +CaCl2 (GLC), calcium lactate (LAC)
The biogenic carbonate crystals (BCC) produced in presence of B. subtilis had different morphological and crystallographic properties, depending of media composition: (a) conditions where the calcium source is not associated to carbon one, non-coupled (GYL and GLC); or (b) where the calcium is attached to the carbon source, coupled (LAC and ACE)

Summary

Introduction

Bacterial CaCO3 mineralization is a phenomenon that occurs in sediments, caves, hot springs, soils and even in monuments and buildings (Ciferri et al 2000; Rusznyák et al 2012; Páramo et al 2015). INDBM and INFBM are passive mechanisms, where physiological activity induces spontaneous precipitation of ions (Knorre and Krumbein 2000) or mineralization are influenced by extracellular polymeric substances (EPS) and biofilm geometry (Dupraz et al 2009), respectively. Ferral‐Pérez et al AMB Expr (2020) 10:174 at 25 °C), oversaturation of Ca2+ and CO32−, and availability of nucleation sites (Dupraz et al 2009) It has been demonstrated the occurrence of B. subtilis culture alkalinization in rich media (Robinson et al 1991) probably due to spontaneous extracellular proteins, or amino acids deamination (Dupraz et al 2009). Some Bacillus species could accelerate the hydration of C O2(g) through carbonic anhydrase activity (Dhami et al 2014)

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