Isolation of biosurfactant producers, optimization and properties of biosurfactant produced by Acinetobacter sp. from petroleum-contaminated soil

Abstract

Aims: To screen and identify biosurfactant producers from petroleum‐contaminated soil; to use response surface methodology (RSM) for medium optimization to enhance biosurfactant production; and to study the properties of the newly obtained biosurfactant towards pH, temperature and salinity. Methods and Results: We successfully isolated three biosurfactant producers from petroleum‐contaminated soil and identified them through 16S rRNA sequence analysis, which exhibit the highest similarities to Acinetobacter beijerinckii (100%), Kocuria marina (99%) and Kineococcus marinus (99%), respectively. A quadratic response model was constructed through RSM designs, leading to a 57·5% increase of the growth‐associated biosurfactant production by Acinetobacter sp. YC‐X 2 with an optimized medium: beef extract 3·12 g l−1; peptone 20·87 g l−1; NaCl 1·04 g l−1; and n‐hexadecane 1·86 g l−1. Biosurfactant produced by Acinetobacter sp. YC‐X 2 retained its properties during exposure to a wide range of pH values (5–11), high temperatures (up to 121°C) and high salinities [up to 18% (w/v) Na+ and Ca2+], which was more sensitive to Ca2+ than Na+. Conclusions: Two novel biosurfactant producers were isolated from petroleum‐contaminated soil. Biosurfactant from Acinetobacter sp. YC‐X 2 has good properties to a wide range of pH, high temperature and high salinity, and its production was optimized successfully through RSM. Significance and Impact of the Study: The fact, an increasing demand of high‐quality surfactants and the lack of cost‐competitive bioprocesses of biosurfactants for commercial utilization, motivates researchers to develop cost‐effective strategies for biosurfactant production through isolating new biosurfactant producers with special surface‐active properties and optimizing their cultural conditions. Two novel biosurfactant producers in this study will widen our knowledge about this kind of micro‐organism. This work is the first application of RSM designs for cultural optimization of biosurfactant produced by Acinetobacter genus and the first report that biosurfactant may be more sensitive to Ca2+ than Na+.

Statistical Design, a Powerful Tool for Optimizing Biosurfactant Production: A Review

“…However, optimum Bs production is generally near neutral pH, although some reports suggest a slight increase in pH from 7-8.5 [10,28]. Normally, the best temperatures for Bs production reported are in the range of 35-40 • C [28].…”

“…Chen et al [10] decided to optimize the production of a Bs from Acinetobacter sp. YC-X 2 that showed stability under high temperatures, salinity, and harsh pH conditions.…”

Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery

“…The morphological, physiological, and phylogenetic characteristics of the isolated strains were analyzed following Bergey’s Manual of Systemic Bacteriology and SSU rRNA sequencing, as previously described by Chen et al (2012).…”

Medium optimization for biosurfactant production by Rhodococcus ruber TD2 using response surface methodology

“…Trong khi phương pháp nghiên cứu 1 yếu tố tại 1 thời điểm không xác định được sự tác động qua lại giữa các yếu tố biến thiên của thành phần môi trường nuôi cấy để dự đoán điều kiện thuận lợi nhất cho sinh trưởng và tạo sản phẩm của vi sinh vật thì phương pháp bề mặt đáp ứng đã khắc phục được nhược điểm đó [15]. Với ưu điểm là có thể tìm được điều kiện tối ưu nhất cho sinh tổng hợp sản phẩm từ một số thực nghiệm tương đối nhỏ, phương pháp này ngày càng được ứng dụng rộng rãi để tối ưu hóa thành phần môi trường tạo CHHBMSH từ vi sinh vật [1,3,8,14,15] [14,15].…”