Rock phosphate dissolution by specific yeast

Abstract

Phosphate solubilizing yeast (PSY) were isolated from rhizosphere, non-rhizosphere and fruits from Bhavnagar district. The potential of 25 yeasts were analyzed on the basis of phosphate solubilizing zone to growth on solid medium denoted as solubilization index (SI) which ranged from 1.10 to 1.50. Among 25 yeast isolates, 6 yeast belonging to genus Saccharomyces (2), Hansenula, Klockera, Rhodotorula and Debaryomyces exhibited highest SI (1.33-1.50) were further examined for in vitro tricalcium phosphate (TCP) and low grade rock phosphate (RP) solubilization. TCP proved superior to RP with all the yeasts. Within low grade RPs tested, except isolate Y5, all isolates showed maximum solubilization with Hirapur RP (HRP) ranging from 7.24 to 19.30 mg% P 2 O 5 . Among six PSY screened, Debaryomyces hansenii showing maximal HRP solubilization was chosen for further physiological studies. Maximum HRP solubilization was expressed in following condition: pH optima 7.0, temperature optima 28°C and optimal period of incubation were 15 days. Acidic pH of the spent media was a constant feature in all the cases. No correlation could be established between fi nal acidity produced by yeasts and the quantity of phosphate liberated.

Isolation and Characterization of Phosphate-Solubilizing Bacteria from Rhizosphere Soil

“…The dominant representatives identified are listed in Table 1: Proteous vulgaris (PR1), Klebsiella pneumoniae (PR2), Enterobacter aerogenes (PR4), Burkholederia cepacia (BR1), Citrobacter freundii (BR2), Acinetobacter lwoffii (SR1), Proteous vulgaris (SR2), Pseudomonas fluorescens (GR1), Burkholederia cepacia (PtR1), Klebsiella pneumoniae (oR1), Citrobacter freundii (FR1), Acinetobacter lwoffii (cR1). Similar results related to isolation, screening and identification have been found by different scientists (7,13,21,27,36). Similarly, Haque and Dave (14) isolated A. lwoffii and studied the rhizosphere soil of different regions and examined the promotion of plant growth.…”

“…P-solubilization, however, is a complex phenomenon and depends on various nutritional and physiological factors, cultivation conditions, etc. (8,21,29).…”

Phosphate Solubilizing Yeast Isolated and Characterized from Teff Rhizosphere Soil Collected from Gojam; Ethiopia

“…Most efficient phosphate solubilizer on Pikovskaya's agar plates with PSI = 3.29. Whereas among fungi P. canescenssho wed highest solubilizing index Nahas [32]. Phosphate solubilization index (PSI) values up to 2.4 have been recorded for Aspergillus niger, with values of 3.1 for Penicillium italicum and 3.0 for Paecilomyces lilacinus [33,34].…”

Phosphate-Solubilizing Microorganisms: A Critical Review

“…Recently, aluminium and rock phosphate solubilization by a specifi c Penicillium sp. and yeast was studied by Xiao et al ( 2013b ) and Narsian et al ( 2010 ), respectively. Unlike their bacterial counterparts, PSF were able to retain P-solubilization trait even after several subcultures.…”