Isolation, identification, and characterization of an Aspergillus niger bioflocculant-producing strain using potato starch wastewater as nutrilite and its application.

Shengyan Pu,Daili Deng,Yan Zhou,Xingying Xiong,Hui Ma,Shengyang Xue,Rongxin Zhu,Vijai Gupta

doi:10.1371/journal.pone.0190236

Shengyan Pu, Daili Deng + Show 6 more

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https://doi.org/10.1371/journal.pone.0190236

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Abstract

A bioflocculant (MBFA18) was produced by Aspergillus niger (A18) using potato starch wastewater (PSW) as nutrients. The cultivation processes and flocculating treatment for PSW purification were systematically studied. The flocculating rate of the MBFA 18 achieved 90.06% (kaolin clay) under the optimal cultivation condition (PSW with 5950 mg/L COD, 20 g/L glucose, 0.2 g/L urea and without phosphorus source addition and pH adjustment). Furthermore, effects of flocculant dosage, initial pH, coagulant aid (CaCl2) addition and sedimentation time on the PSW treatment were discussed and studied in detail. The optimum flocculation treatment conditions were determined according to the treatment efficiency, cost and flocculation conditions. During the PSW treatment, 2 mL/L bioflocculant (1.89 g/L) dosage and 0.5 mol/L coagulant aid addition were applied without pH adjustment and 91.15% COD and 60.22% turbidity removal rate could be achieved within 20 min. The comparative study between the bioflocculant and conventional chemical flocculants showed excellent flocculating efficiency of MBFA 18 with lower cost (4.7 yuan/t), which indicated that the bioflocculant MBFA 18 produced in PSW substrate has a great potential to be an alternative flocculant in PSW treatment.

Highlights

China is the biggest producer of potato starch which accounts for more than 85.9% of the world annual production, the domestic potato starch wastewater (PSW) has been becoming a serious problem that needs to be settledd urgently [1]
The bioflocculant-producing microorganism was isolated from 10 cm beneath the soil surface in the Garden of Chengdu University of Technology, Sichuan, China. 1.0 g soil sample was added into 250 mL conical flask with 99 mL sterilized water and glass beads, thoroughly stirring for 20 min to obtain 10−2 g/mL soil suspension
This study revealed that PSW could serve as a suitable substrate for the bioflocculant producing microorganism- Aspergillus niger (A18) isolated from soil sample

Summary

Introduction

China is the biggest producer of potato starch which accounts for more than 85.9% of the world annual production, the domestic potato starch wastewater (PSW) has been becoming a serious problem that needs to be settledd urgently [1]. Two primary issues of PSW, high biological oxygen demand (BOD) and large output amount, bring huge challenges to the traditional treatment technology [2,3,4]. A bioflocculant-producing strain of Aspergillus niger by potato starch sewage substrate and its application and G-YZ80) and the Project Funded by China Postdoctoral Science Foundation (2015T80966). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

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