Novel high pH induction and carbon dioxide emission reduction coupling microalgae harvesting method

Abstract

The invention discloses a novel high pH induction and carbon dioxide emission reduction coupling microalgae harvesting method. Microalgae cells are self-settled and efficiently concentrated by using high pH induction so that high-efficiency and low-cost harvesting is realized. A CO2 emission reduction carbon replenishing technology is coupled, acidic gas CO2 is efficiently absorbed by using harvested high-alkali supernate to ensure that the pH of the high-alkali supernate is reduced to be a level (pH>=8.2) suitable for microalgae growth, high-efficiency carbon replenishing of a culture medium is realized, the supernate after havesting can be recycled, and the harvesting cost and fertilizer cost during large-scale cultivation of the microalgae are greatly lowered.

Description

Technical field: [0001] The invention relates to a method for harvesting microalgae cultures, in particular to a new method for harvesting microalgae induced by high pH and coupled with carbon dioxide emission reduction. Background technique: [0002] Microalgae are rich in nutrition, rich in protein, vitamins and polyunsaturated fatty acids, and have excellent application prospects in industrial fields such as health food, biological bait, medicine, and biofuel. However, the key problem currently hindering the development of the microalgae industry is the high cost of cultivation and production, and the cost of harvesting is one of the main factors limiting the cost of microalgae cultivation. In the culture of microalgae, the chemical flocculation method, that is, adding a small amount of macromolecular or small molecular compounds that can flocculate cells into the culture, concentrates the cells, and then centrifuges or filters the concentrated cells to achieve cell colle...

AI Technical Summary

Problems solved by technology

This method still has the problem of high cost, but because the pH range of the optimal growth of most unicellular microalgae currently cultivated is close to neutral (6.5-7.5), the cost of induction by adding alkali is relatively high, and the post-harvest A large amount of acid added to neutralize pH includes hydrochloric acid, sulfuric acid or carbon dioxide, which will increase new costs

At the same time, if this method uses hydrochloric acid and sulfuric acid to neutralize the high pH harvest supernatant, although the discharge of the medium can be reduced to a certain extent and the medium can be recycled, but as the cycle time prolongs, the concentration of the culture medium can be greatly increased. Salinity inhibits cell growth

Adding carbon dioxide seems to be a more reasonable choice. It can supplement the carbon source without changing the salinity, but the cost of adding lye is still high, and carbon dioxide is a weak acid after dissolved in water, and the amount added is large, and the acidification end point is The pH (6.5-7.5) suitable for the growth of microalgae, within this range, the CO dissolved in the medium 2 Will spill a lot, resulting in waste of carbon source