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Isolation and Fingerprint Differentiation of Lactic Acid Bacteria from Swedish Grain Legumes Phaseolus vulgaris and Pisum sativum

Isolation and Fingerprint Differentiation of Lactic Acid Bacteria from Swedish Grain Legumes Phaseolus vulgaris and Pisum sativum

Cecilia Mayer
Göteborg : Chalmers tekniska högskola, 2016. 44 s.
[Examensarbete på avancerad nivå]

To stimulate Swedish agriculture into becoming more environmentally friendly and self-sufficient it is important to create added value to sustainably cultivated crops. Grain legumes, such as beans and lentils, need to become more accessible, economically sustainable and attractive for both farmer and consumer. As a way of achieving this, development of new food products based on local crops is important. Fermentation is a well-known process in the food industry that can provide several positive nutritional effects to raw material such as grain legumes. There is however a need to develop starter cultures primarily adapted and aimed for plant based raw material. As a first step, lactic acid bacteria (LAB) that naturally inhabit grain legumes were isolated to create a microbiological library. Twenty-three samples from 6 different varieties of Common bean, Phaseolus vulgaris and 2 varieties of peas, Pisum sativum were collected from different locations on Öland and analyzed for LAB. The samples were ground and enriched in liquid MRS medium, or fermented in solid state, before being plated and incubated anaerobically on MRS agar. Candidate LAB colonies were re-plated until isolated strains were obtained. Biochemical analysis was made for a total of 253 isolates whereof 174 stained gram positive and was oxidase, catalase and KOH string test negative. These were selected as presumed lactic acid bacteria. DNA from the isolates were extracted using either one of two methods, phenol:chloroform extraction or by a Qiagen kit. To enable isolates to be distinguished from each other and identify duplicates in the library, a rep-PCR protocol was developed. Following evaluation of three different protocols previously described, a new protocol was adapted from these. The final rep-PCR protocol and following electrophoresis conditions gave a genomic fingerprint with satisfactory resolution after many trials and adjustments. The protocol was applicable on the isolated bacteria and these can serve as the basis of a first screening for fermenting organisms with properties suitable for Swedish grain legumes

Nyckelord: lactic acid bacteria, rep-PCR, electrophoresis, grain legumes, sustainable agriculture, sustainable food, Swedish agriculture

Publikationen registrerades 2016-09-12.

CPL ID: 241658

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