The co-aggregates were centrifuged twice at 5000×g for 10 min, and resuspended in 10 mM of phosphate buffer. After five min of sonication, the cells were centrifuged at 5000×g for five min. Pellets were collected and suspended in the co-aggregate buffer.The percentage of co-aggregation was estimated. Sonication was done for one minute and the suspension was incubated at 50 °C for three hours. The cells were transferred to co-aggregate buffer and the stability was determined as described earlier