Kasan Nor Azman, Ghazali Nurarina Ayuni, Ikhwanuddin Mhd, Ibrahim Zaharah
Institute of Tropical Aquaculture (AKUATROP), Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Malaysia.
Department of Biological Sciences, Faculty of Biosciences and Bioengineering, Universiti Teknologi Malaysia, 81300 Skudai, Johor, Malaysia.
Pak J Biol Sci. 2017;20(6):306-313. doi: 10.3923/pjbs.2017.306.313.
A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc.
For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC.
Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp.
In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.
一种新的绿色技术——“生物絮团技术”被开发出来，该技术在优化凡纳滨对虾（Litopenaeus vannamei）产量的同时，减少对环境的破坏。生物絮团聚集体中的微生物群落负责减少换水，并产生可作为凡纳滨对虾补充饲料的微生物蛋白。本研究旨在分离和鉴定潜在的产生物絮凝剂细菌，用作快速形成生物絮团的接种物。
为了本研究的目的，通过表型和16S rDNA序列分析，对凡纳滨对虾养成池塘养殖0天、30天和70天期间的细菌群落进行分离和鉴定。然后通过系统发育树分析评估分离细菌之间的系统发育关系。采用单因素方差分析（ANOVA）比较每个养殖天数的微生物群落差异。
在125株细菌分离物中，成功鉴定出9种来自生物絮团的细菌。这些细菌分别被鉴定为嗜盐栖热单胞菌（Halomonas venusta）、海生盐单胞菌（H. aquamarina）、副溶血性弧菌（Vibrio parahaemolyticus）、婴儿芽孢杆菌（Bacillus infantis）、蜡样芽孢杆菌（B. cereus）、沙福芽孢杆菌（B. safensis）、蠕形普罗威登斯菌（Providencia vermicola）、海水硝酸盐还原菌（Nitratireductor aquimarinus）和假交替单胞菌属（Pseudoalteromonas sp.）。通过系统发育分析，这些分离物属于盐单胞菌属（Halomonas sp.）、弧菌属（Vibrio sp.）、芽孢杆菌属（Bacillus sp.）、普罗威登斯菌属（Providencia sp.）、硝酸盐还原菌属（Nitratireductor sp.）和假交替单胞菌属（Pseudoalteromonas sp.）下的变形菌门和厚壁菌门。
在本研究中，成功鉴定出了产生物絮凝剂细菌，它们是形成生物絮团以减少水污染、实现可持续水产养殖业的理想候选者。在生物絮团形成的所有阶段都存在盐单胞菌属和芽孢杆菌属，这加强了对这些物种作为快速形成生物絮团接种物能力进行新开发的需求。
